scholarly journals Role of serum IgA. Hepatobiliary transport of circulating antigen.

1981 ◽  
Vol 153 (4) ◽  
pp. 968-976 ◽  
Author(s):  
M W Russell ◽  
T A Brown ◽  
J Mestecky
Keyword(s):  
Molecular Weight ◽  
Human Serum Albumin ◽  
Gel Filtration ◽  
Low Molecular Weight ◽  
Serum Iga ◽  
Circulating Antigen ◽  
Circulating Antigens ◽  
Iga Antibody ◽  
Immune Spleen Cell

The IgA mediated hepatobiliary excretion of antigen from the circulation was studied using a radiolabeled haptenated protein (dinitrophenyl-human serum albumin) injected intravenously in mice together with monoclonal anti-dinitrophenyl antibodies of different immunoglobulin classes. Antibodies were obtained from ascitic fluids of mice bearing the MOPC315 myeloma (IgA), or immune spleen cell hybridomas (IgG and IgM). IgA antibody brought about the transport of large amounts of antigen from the circulation to the bile during 1-3h. Analysis of bile by gel filtration showed that a large part of the transported antigen remained intact and complexed with IgA. Neither IgA of different specificity nor anti-dinitrophenyl IgM medicated biliary transport of antigen. With anti-dinitrophenyl IgG, only small amounts of low molecular weight fragments of labeled antigen were found in he bile. Preformed immune complex of radiolabeled antigen and IgA antibody were rapidly transported from the circulation to the bile, resulting in threefold-higher levels of radioactivity in bile than in serum. It is proposed that an important function of serum IgA is to mediate the hepatobiliary excretion of corresponding circulating antigens.

scholarly journals Control of the fructose 6-phosphate/fructose 1,6-bisphosphate cycle in isolated hepatocytes by glucose and glucagon. Role of a low-molecular-weight stimulator of phosphofructokinase

1980 ◽  
Vol 192 (3) ◽  
pp. 887-895 ◽  
Author(s):  
Emile Van Schaftingen ◽  
Louis Hue ◽  
Henri-Géry Hers
Keyword(s):  
Molecular Weight ◽  
Incubation Medium ◽  
Liver Extract ◽  
Gel Filtration ◽  
Isolated Hepatocytes ◽  
Low Molecular Weight ◽  
Experimental Conditions ◽  
Fructose 1,6 Bisphosphate ◽  
Acid Labile

1. Recycling of metabolites between fructose 6-phosphate and triose phosphates has been investigated in isolated hepatocytes by the randomization of carbon between C(1) and C(6) of glucose formed from [1-14C]galactose. 2. Randomization of carbon atoms was regularly observed with hepatocytes isolated from fed rats and was then little influenced by the concentration of glucose in the incubation medium. It was decreased by about 50% in the presence of glucagon. 3. Randomization of carbon atoms by hepatocytes isolated from starved rats was barely detectable at physiological concentrations of glucose in the incubation medium, but was greatly increased with increasing glucose concentrations. It was nearly completely suppressed by glucagon. These large changes can be attributed to parallel variations in the activity of phosphofructokinase. 4. The main factors that appear to control the activity of phosphofructokinase under these experimental conditions are the concentration of fructose 6-phosphate, the concentration of fructose 1,6-bisphosphate and also the affinity of the enzyme for fructose 6-phosphate. 5. The affinity of phosphofructokinase for fructose 6-phosphate was diminished by incubation of the cells in the presence of glucagon and also by filtration of an extract of hepatocytes through Sephadex G-25 and by purification of the enzyme. When assayed at 0.25 or 0.5mm-fructose 6-phosphate, the activity of phosphofructokinase present in a liver Sephadex filtrate was increased by a low-molecular-weight effector, which could be isolated from a liver extract by ultrafiltration, gel filtration or heat treatment, but was rapidly destroyed in trichloroacetic acid, even in the cold. This effector appears to be a highly acid-labile phosphoric ester. Its concentration was greatly increased in hepatocytes incubated in the presence of glucose and was decreased in the presence of glucagon.

In Vivo Studies on the Inhibition of Coagulation by Fractionated Heparin and by a Heparin Analogue I. Effects of Heparin Fractions

1981 ◽  
Vol 46 (03) ◽  
pp. 612-616 ◽  
Author(s):  
U Schmitz-Huebner ◽  
L Balleisen ◽  
F Asbeck ◽  
J van de Loo
Keyword(s):  
Molecular Weight ◽  
Day Treatment ◽  
Gel Filtration ◽  
Weight Fraction ◽  
In Vivo Studies ◽  
Low Molecular Weight ◽  
High Molecular Weight Fraction ◽  
Platelet Factor ◽  
Heparin Fractions

SummaryHigh and low molecular weight heparin fractions obtained by gel filtration chromatography of sodium mucosal heparin were injected subcutaneously into six healthy volunteers and compared with the unfractionated substance in a cross-over trial. Equal doses of 5,000 U were administered twice daily over a period of three days and heparin activity was repeatedly controlled before and 2, 4, 8 hrs after injection by means of the APTT, the anti-Xa clotting test and a chromogenic substrate assay. In addition, the in vivo effect of subcutaneously administered fractionated heparin on platelet function was examined on three of the volunteers. The results show that s.c. injections of the low molecular weight fraction induced markedly higher anti-Xa activity than injections of the other preparations. At the same time, APTT results did not significantly differ. Unfractionated heparin and the high molecular weight fraction enhanced ADP-induced platelet aggregation and collagen-mediated MDA production, while the low molecular weight fraction hardly affected these assays, but potently inhibited thrombin-induced MDA production. All heparin preparations stimulated the release of platelet Factor 4 in plasma. During the three-day treatment periods, no side-effects and no significant changes in the response to heparin injections were detected.

scholarly journals Simultaneous Determination of Human Serum Albumin and Low-Molecular-Weight Thiols after Derivatization with Monobromobimane

Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3321
Author(s):  
Katarzyna Kurpet ◽  
Rafał Głowacki ◽  
Grażyna Chwatko
Keyword(s):  
Molecular Weight ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Simultaneous Determination ◽  
Reversed Phase ◽  
Fluorescence Labeling ◽  
Detector Response ◽  
Low Molecular Weight

Biothiols are extremely powerful antioxidants that protect cells against the effects of oxidative stress. They are also considered relevant disease biomarkers, specifically risk factors for cardiovascular disease. In this paper, a new procedure for the simultaneous determination of human serum albumin and low-molecular-weight thiols in plasma is described. The method is based on the pre-column derivatization of analytes with a thiol-specific fluorescence labeling reagent, monobromobimane, followed by separation and quantification through reversed-phase high-performance liquid chromatography with fluorescence detection (excitation, 378 nm; emission, 492 nm). Prior to the derivatization step, the oxidized thiols are converted to their reduced forms by reductive cleavage with sodium borohydride. Linearity in the detector response for total thiols was observed in the following ranges: 1.76–30.0 mg mL−1 for human serum albumin, 0.29–5.0 nmol mL−1 for α-lipoic acid, 1.16–35 nmol mL−1 for glutathione, 9.83–450.0 nmol mL−1 for cysteine, 0.55–40.0 nmol mL−1 for homocysteine, 0.34–50.0 nmol mL−1 for N-acetyl-L-cysteine, and 1.45–45.0 nmol mL−1 for cysteinylglycine. Recovery values of 85.16–119.48% were recorded for all the analytes. The developed method is sensitive, repeatable, and linear within the expected ranges of total thiols. The devised procedure can be applied to plasma samples to monitor biochemical processes in various pathophysiological states.

HEMODIALYSIS OF THE RAT

1966 ◽  
Vol 44 (5) ◽  
pp. 849-859 ◽  
Author(s):  
Sumner M. Robinson ◽  
David A. Hurwitz ◽  
Robert Louis-Ferdinand ◽  
William F. Blatt
Keyword(s):  
Molecular Weight ◽  
Gel Filtration ◽  
Low Molecular Weight

A technique is described for hemodialysis of either anesthetized or non-restrained rats. In the apparatus the dialysis plates of an autoanalyzer system are used with only minor modification. The efficiency of this method has been evaluated with regard to the clearance of saccharides, both in vitro and in vivo, as well as the extraction of nitrogenous low molecular weight moieties from circulating blood. Approximately 50% of the dialyzable material was obtained in a 1-hour dialysis. Further fractionation of the dialyzate was accomplished by gel filtration (Sephadex G-25).

Anti-Inflammatory Activity in the Low Molecular Weight Fraction of Commercial Human Serum Albumin (LMWF5A)

2015 ◽  
Vol 37 (1) ◽  
pp. 55-67 ◽  
Author(s):  
Gregory W. Thomas ◽  
Leonard T. Rael ◽  
Charles W. Mains ◽  
Denetta Slone ◽  
Matthew M. Carrick ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Human Serum Albumin ◽  
Serum Albumin ◽  
Human Serum ◽  
Weight Fraction ◽  
Inflammatory Activity ◽  
Low Molecular Weight ◽  
Anti Inflammatory

Polyamine metabolism and function

1982 ◽  
Vol 243 (5) ◽  
pp. C212-C221 ◽  
Author(s):  
A. E. Pegg ◽  
P. P. McCann
Keyword(s):  
Molecular Weight ◽  
Tissue Growth ◽  
Polyamine Metabolism ◽  
Organic Cations ◽  
Low Molecular Weight ◽  
Polyamine Biosynthesis ◽  
Polyamine Content ◽  
And Function ◽  
Specific Inhibitors

Polyamines are ubiquitous organic cations of low molecular weight. The content of these amines is closely regulated by the cell according to the state of growth. The reactions responsible for the biosynthesis and interconversion of the polyamines and their precursor putrescine are described and the means by which polyamine content can be varied in response to exogenous stimuli are discussed. The role of polyamines in the cell cycle, cell division, tissue growth, and differentiation is considered. Recent studies using highly specific inhibitors of polyamine biosynthesis such as alpha-difluoromethylornithine to prevent accumulation of polyamines have indicated that the synthesis of polyamines is intimately associated with these processes. Such inhibitors have great potential for investigation of the cellular role of polyamines.

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