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K Nustad

Publications and source records attributed to K Nustad.

At least 73 records · Page 4Linked to original sources
PubMed1984

Hydrophilic monodisperse particles as solid-phase material in immunoassays: comparison of shell-and-core particles with compact particles.

Hydrophilic monodisperse shell-and-core particles with a density of 1.07 were superior to heavier compact particles as a solid-phase material for immunoassays. The shell-and-core particles formed a semistable suspension for 24 h and were easily collected by centrifugation. The hydroxyl groups of the particles were activated with two sulfonyl chlorides. The most reactive one, tresyl chloride, gave rapid chemical coupling of antibodies, whereas tosyl chloride favored a rapid hydrophobic adsorption which was followed by slow chemical coupling. The solid-phase sheep antirabbit IgG made was used as a separation agent in several immunoassays and gave solid-phase primary antibodies by immunoadsorption of rabbit antibodies.

Animals↗
PubMed1984

Mouse monoclonal anti rabbit IgG coupled to monodisperse polymer particles. Comparison with polyclonal antibodies in radioimmunoassay for thyroid hormones.

A solid phase second antibody was prepared by covalent coupling of a mouse monoclonal anti rabbit IgG to monodisperse particles. This preparation was compared with immunosorbent purified sheep anti rabbit IgG antibodies coupled to the same particles. The monoclonal antibody bound rabbit IgG with a dissociation constant of 3 X 10(-11) L/mol, and the binding was Fc specific. The sheep antibodies had a similar Kd and about 75% of the activity was directed against the Fc portion of IgG. The binding capacity per mol of both solid phase antibodies was 0.7 mol of rabbit IgG. Monoclonal and polyclonal solid phase antibodies were equally effective as separating agents in various radioimmunoassays. Direct coupling of the rabbit antibodies to the solid phase resulted in a marked loss of binding capacity for the respective thyroid hormones. However, when rabbit anti-thyroxine or anti-triiodothyronine were preadsorbent to second-antibody-coated particles the binding capacities of the former antibodies were well preserved.

Animals↗
PubMed1983

Excess antibody immunoassays for rat glandular kallikreins. Measurement of kallikrein from different organs in the presence of cross-reacting antigens.

An immunoradiometric assay has previously been developed for measurement of rat glandular kallikrein. In the present paper, further studies on the specificity and sensitivity of the method are described. Problems of interference of immunologically cross-reacting antigens were overcome by proper preabsorption of the antibody. A method was thus established in which enzymatic activity of the immunoreactive kallikrein could be measured even in the presence of enzymes sharing immunological determinants and substrate specificity with kallikrein. Two variants of the immunoradiometric assay have been evaluated. A simplified version with simultaneous addition of all reagents gave results equal to those obtained in the original assay. A further modification with delayed addition of the solid-phase antibody, gave considerable improvement in assay sensitivity.

Animals↗
PubMed1983

Excess antibody immunoassay for rat glandular kallikrein. Monosized polymer particles as the preferred solid phase material.

The development of an excess antibody assay for rat glandular kallikrein is described. This assay permits immunological determination of kallikrein as well as a simultaneous specific measurement of kallikrein enzymatic activity. The assay is based on coupling of immunopurified anti-kallikrein immunoglobulin to a solid phase. In a first incubation step, kallikrein was bound to the immobilized antibody. Determination of kallikrein was subsequently done in a second incubation step; immunologically by addition of iodinated anti-kallikrein antibody, or enzymatically by a kallikrein substrate. Enzymatic quantification could also be followed by immunological measurements on the same sample. Comparison of Sepharose, cellulose, and acrylate based polymer particles proved the latter to be the best matrix in this assay. The main advantage of the polymer particles was the low non-specific binding of labelled antibody.

Animals↗
PubMed1982

Prostatic acid phosphatase, purification and iodination using Iodogen.

Prostatic acid phosphatase was purified from prostatic adenomas. The procedure involved chromatography on Concanavalin A-Sepharose, DEAE-cellulose, Bio-Gel P-150 and L-tartrate-Sepharose. The purified phosphatase hydrolyzed p-nitrophenyl phosphate at a rate of 270 mumol . mg-1 . min-1 (25 degrees C) and showed homogeneity upon polyacrylamide gel electrophoresis in sodium dodecyl sulfate. The final prostatic acid phosphatase preparation was pure and the antisera were monospecific as judged by the highly sensitive technique of crossed immunoelectrophoresis. Of the procedures evaluated for the iodination of the purified enzyme, oxidation with Iodogen was found to give the best iodinated product.

Acid Phosphatase↗
PubMed1980

Isolation of rat submandibula kallikreins by using immunoadsorption chromatography.

A one-step immunoadsorption method for the isolation of glandular kallikreins is described using the immunoglobulin fraction from rabbit anti-(rat glandular kallikrein) serum coupled to CNBr-activated Sepharose 4B. The adsorptions of 125I-labelled kallikrein or unlabelled kallifrein from 100 000 g submandibular gland supernatants were more than 97% complete. The elution of kallikrein from the immunoadsorbent using guanidine hydrochloride gave about 20% yield, which could be increased up to 70% by including 0.5% bovine serum albumin in the elution buffer. The electrophoretic mobility of eluted submandibular 125I-labelled kallikrein or submandibular glandular kallikrein was not altered after affinity chromatography, as judged by conventional polyacrylamide disc-gel electrophoresis or by polyacrylamide-gel electrophoresis in the presence of sodium dodecyl sulphate. In addition, the specific esterase and the kininogenase activities of isolated submandibular kallikreins were more than 90% of those of the reference enzyme. This procedure, which results in the isolation of immunologically and biologically active submandibular kallikrein, may also be used for purificaton of other glandular kallikreins that show immunological homology.

Animals↗
PubMed1980

Intraglandular transport of 125I-glandular kallikrein in the rat submandibular salivary gland.

The transport of radiolabelled rat submandibular gland kallikrein was studied after local administration to the resting and activated rat submandibular gland. The iodinated kallikrein was electrophoretically, immunologically, and biologically indistinguishable from the intact enzyme. After intraductal and intraglandular application the radioactivity in venous effluent was quantitated and characterized. As judged by gel-filtration 125I-kallikrein in venous effluent eluted at a position similar to that seen when the iodinated enzyme was mixed with plasma, but earlier than the elution of 125I-kallikrein in buffer. In plasma, therefore, glandular kallikrein is probably bound to macromolecules. The radioactive fractions in venous effluent did not contain free iodine. Maximum concentration of 125I-kallikrein in venous effluent of resting glands was repeatedly reached about 20 min after intraductal administration. Moreover, the ductal epithelium represented the main permeation barrier since after intraglandular application the maximum venous 125I-kallikrein concentration was reached almost immediately. In activated gland (parasympathetic and sympathetic nerve stimulation), the venous 125I-kallikrein concentration was inversely related to glandular blood flow. We conclude that kallikrein present in the duct lumen or in the interstitium is able to reach the circulation, thereby making possible the local generation of plasma-kinins.

Animals↗
PubMed1980

Immunohistochemical localization of kallikrein in human pancreas and salivary glands.

The localization of kallikrein in human exocrine organs was studied with a direct immunofluorescence method. In the submandibular and parotid salivary glands, kallikrein was found apically in the striated duct cells whereas it was absent from the main excretory ducts or present only as a weak luminal rim. Kallikrein was not found in the acinar cells or in cells of the intercalated ducts. In the pancreas, kallikrein-specific fluorescence was seen in the granular portion of the acinar cells, whereas the islets of Langerhans and ductal cells were unstained.

Epitopes↗
PubMed1979

Origin of kallikrein in rat and human exocrine glands and kidney.

1. The cellular localization of kallikrein was investigated in rat and human exocrine glands and kidney by a direct immunofluorescence technique. 2. Kallikrein was found in the duct system of the rat and human major salivary glands. 3. Kallikrein was found in the distal tubular cells of the rat kidney. Attempts to localize kallikrein in the human kidney were unsuccessful. 4. In the rat and human pancreas, kallikrein was found as a pro-enzyme in the acinar cells.

Animals↗
PubMed1977

The immunological similarity of rat glandular kallikreins.

The immunological properties of the submandibular kallikrein, urinary kallikrein, pancreatic kallikrein and pancreatic prekallikrein of the rat were studied by immunodiffusion, immunoelectrophoresis and radioimmunoassay. Although they behaved differently electrophoretically, all the antigens showed identical immunological behaviour. The implications of this are discussed.

Animals↗