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Biomedical subjects

L Johansen

Publications and source records attributed to L Johansen.

52 records · Page 3Linked to original sources
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

Immunohistochemical localization of tonin and its relation to kallikrein in rat salivary glands.

Tonin and kallikrein are serine proteases present in high concentrations in the submandibular gland of the rat. These enzymes release the vasoactive peptides angiotensin II and lysyl-bradykinin from the precursors angiotensinogen and kininogen, respectively. Tonin and kallikrein were purified from homogenates of rat submandibular gland, and antisera against each protein were raised in rabbits. The anti-kallikrein antibody also reacted with tonin, showing partial cross-reactivity between kallikrein and tonin when tested by double immunodiffusion and by immunoelectrophoresis. The anti-tonin antibody did not appear to react with kallikrein in immunodiffusion systems. The cellular localization of tonin was investigated by the indirect immunofluorescence and the peroxidase-antiperoxidase techniques. In the granular tubular cells tonin-specific staining was abundantly present with a granular distribution; in the striated duct cells tonin-specific staining was observed as a thin luminal rim. Tonin was not detected in any other structures of the gland. When the localization of tonin was compared with that of kallikrein, both enzymes were found within the same granular tubular cells. However, more kallikrein than tonin was detected in the striated duct cells. Furthermore, kallikrein but not tonin was found in the ductal cells of the parotid and sublingual glands.

Animals↗
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↗
PubMed1979

Uptake of 3H-L-carnitine by isolated rat epididymal tubules.

The uptake of radiolabeled L-carnitine has been studied in isolated epididymal tubules from the rat. The uptake of 3H-L-carnitine increases with a temperature coefficient KT of 0.22 nmol carnitine.mg protein-1 in the intermal 22--31 degrees and with a low uptake at 4 degrees C. The uptake of radiolabeled carnitine (as percent) is reduced at high concentrations of L-carnitine, by deoxycarnitine but not by D-carnitine. This uptake mechanism is especially active in the distal caput and corpus segments of the epididymis. Thus, an uptake mechanism for carnitine is present in the epididymal cells which besides the carnitine uptake in spermatozoa is responsible for the dramatic increase in carnitine concentration in cauda epididymis.

Animals↗
PubMed1978

Carnitine-binding related supressed oxygen uptake by spermatozoa.

L-carnitine (25 mM) reduced oxygen uptake immediately by 40% in ejaculated bovine spermatozoa, but not in ejaculated human spermatozoa or in spermatozoa from bovine and rat epididymis. [3H]-L-carnitine was bound five times as much to ejaculated bovine spermatozoa as to bovine spermatozoa from the cauda epididymis and to human ejaculated spermatozoa. This indicates the presence of a factor in the accessory male sex organs which, through changes in the membrane and/or intracellulary, increases the [3H]-L-carnitine binding sites and makes the spermatozoa susceptible to carnitine inhibition.

Animals↗
PubMed1975

Physiological and biochemical role of the butanediol pathway in Aerobacter (Enterobacter) aerogenes.

Aerobacter (Enterobacter) aerogenes wild type and three mutants deficient in the formation of acetoin and 2,3-butanediol were grown in a glucose minimal medium. Culture densities, pH, and diacetyl, acetoin, and 2,3-butanediol levels were recorded. The pH in wild-type cultures dropped from 7.0 to 5.8, remained constant while acetoin and 2,3-butanediol were formed, and increased to pH 6.5 after exhaustion of the carbon source. More 2,3-butanediol than acetoin was formed initially, but after glucose exhaustion reoxidation to acetoin occurred. The three mutants differed from the wild type in yielding acid cultures (pH below 4.5). The wild type and one of the mutants were grown exponentially under aerobic and anaerobic conditions with the pH fixed at 7.0, 5.8, and 5.0, respectively. Growth rates decreased with decreasing pH values. Aerobically, this effect was weak, and the two strains were affected to the same degree. Under anaerobic conditions, the growth rates were markedly inhibited at a low pH, and the mutant was slightly more affected than the wild type. Levels of alcohol dehydrogenase were low under all conditions, indicating that the enzyme plays no role during exponential growth. The levels of diacetyl (acetoin) reductase, lactate dehydrogenase, and phosphotransacetylase were independent of the pH during aerobic growth of the two strains. Under anaerobic conditions, the formation of diacetyl (acetoin) reductase was pH dependent, with much higher levels of the enzyme at pH 5.0 than at pH 7.0. Lactate dehydrogenase and phosphotransacetylase revealed the same pattern of pH-dependent formation in the mutant, but not in the wild type.

Acetates↗
PubMedDate not supplied

Comparison of PT, aPTT, and factor VII values obtained by concurrent sample collection by direct venipuncture and peripheral venous catheters.

STUDY OBJECTIVE: To compare prothrombin time (PT), activated partial thromboplastin time (aPTT), and factor VII values in concurrent blood samples obtained by direct venipuncture and from a peripheral venous catheter. DESIGN: Concurrent samples obtained from catheters and by direct venipuncture were studied. In a separate crossover bioequivalence assessment of DNA-derived factor VIIa (rFVIIa) from two different batches, sample results of each technique were compared. SETTING: University hospital clinical research unit. PATIENTS: Six patients with hemophilia A under nonbleeding conditions. INTERVENTIONS: The patients received a single dose of rFVIIa 70 micrograms/kg administered by intravenous push over 2 minutes. Concurrent blood samples were collected at 2, 3, 4, 6, 8, 10, and 12 hours after rFVIIa administration. Catheter blood samples were drawn from a three-way stopcock attached to an 18-gauge peripheral venous catheter in the patient's forearm and connected to an intravenous solution of 5% dextrose with half normal saline maintained at a rate of 30 ml/hour. Venipuncture samples were drawn from the opposite arm. MEASUREMENTS AND MAIN RESULTS: The PT and aPTT values were determined by using a BBL Fibrometer (PT) and a Coagamate X-2 with automated aPTT reagent. Blood samples were analyzed for factor VII concentration using the Novo Clot assay. The mean venipuncture-obtained PT (8.9 +/- 1.0 sec) and aPTT (48.7 +/- 13.6 sec) values were numerically equivalent to mean catheter-derived PT (9.0 +/- 1.0 sec) and aPTT (48.3 +/- 12.5 sec) results, as were mean venipuncture and catheter-obtained FVII:C values. CONCLUSIONS: The PT and aPTT values determined after venipuncture and through the peripheral catheter were not statistically different (p > 0.05) when compared by paired or unpaired analysis. Similarly, values of FVII:C measured after venipuncture were statistically equivalent to those after sampling through the peripheral catheter. All six patients preferred the catheter method of blood collection over venipuncture.

Adult↗