[Pain relief in rheumatoid arthritis. Dietary factors can influence the rheumatoid inflammation].
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Arthritis, Rheumatoid↗
Biomedical subjects
G Johansson
Publications and source records attributed to G Johansson.
Is cellobiose oxidase from Phanerochaete chrysosporium a one-electron reductase?
The heme domain of cellobiose oxidase (CBO) from Phanerochaete chrysosporium increases the rate of electron transfer to one-electron acceptors. This conclusion was drawn from comparisons of the rates of reduction of 3,5-t-butyl-o-benzoquinone, triiodide ion, cytochrome c and ferricyanide by intact CBO, FAD fragment and CBO with the heme inactivated by cyanide. The oxidation of cellobiose produced hydrogen peroxide, but the enzyme disturbs peroxidase-based assays by reduction of the product or by direct interaction with the peroxidase. CBO can also degrade hydrogen peroxide in the presence of cellobiose. The 1,2,4,5-tetramethoxybenzene cation radical was rapidly reduced by CBO.
Carbohydrate Dehydrogenases↗
Trichoderma reesei has no true exo-cellulase: all intact and truncated cellulases produce new reducing end groups on cellulose.
Adsorption to and formation of insoluble reducing end groups on cellulose was studied for intact enzymes and catalytic domains, 'cores', of the four major cellulases from Trichoderma reesei, CBH I, CBH II, EG I and EG III. Individual enzymes were incubated with NaBH4-reduced, phosphoric acid swollen Avicel (regenerated cellulose) or with filter paper. Adsorption onto regenerated cellulose was rapid (equilibration reached within 2 min), but was slow onto filter paper (not completed after 24 h). On both substrates, less was bound of the core domains than of the intact enzymes. After reaching a maximum in adsorption, all the core domains except CBH I core were released again. In general, the desorption of the core enzymes was much faster than the rate of substrate conversion. All enzymes produced new reducing end groups on both substrates, and thus none of them is a true exo-cellulase. However, both the rate of formation and the amount was considerably higher for the EG enzymes than for the CBH's, which may justify the classification of cellulases into two groups, although the difference is quantitative rather than qualitative. EG III was the most endo-active of the enzymes, and CBH I the least.
Adsorption↗
Fractionation of erythroblasts with affinity-mediated modifications of their electrical properties using counter-current distribution.
We have previously reported the possibility of modifying the electrical properties of cells by means of their interaction with a specific ligand carrying a polyelectrolyte (Anal Biochem 200: 280-285). This selective modification of receptor-containing cells changed their partition in a charge-sensitive aqueous two-phase system. We here present the fractionation of electrically modified erythroblasts by the use of an automatic multiple-partition procedure, counter-current distribution. The cells were fractionated according to the degree of differentiation of erythroblasts as evaluated from the hemoglobin content as well as the relative activities of the two enzymes, 3-phosphoglycerate kinase and bisphospho-glycerate mutase.
Animals↗
[Nursing in transition needs keen leaders. Interview by Carina Roxström].
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Humans↗
Kinetic studies of the active sites functioning in the quinohemoprotein fructose dehydrogenase.
Steady-state kinetic analysis was performed on the reaction between D-fructose and ferricyanide with the quinohemoprotein fructose dehydrogenase from Gluconobacter species. The D-fructose oxidation dependence on the ferricyanide concentration resulted in a series of parallel reciprocal plots, and the reaction was assumed to proceed by a ping-pong type of mechanism. A reciprocal plot of the reduction of ferricyanide at saturating concentration of D-fructose gave a break which was considered to appear as a result of the two active centers, namely PQQ and heme c functioning. A scheme of action is proposed and the bimolecular rate constant of the D-fructose oxidation, the kcat for PQQ and the electron transfer rate between the PQQH2 and heme c are calculated and account for 2.2 +/- 0.4 x 10(4) M-1 s-1, (93 +/- 14) and (162 +/- 7) s-1, respectively.
Binding Sites↗
Real-time kinetic analysis of limited proteolysis by ion-exchange chromatography using compressed, non-porous agarose beads.
In biotechnology there is a great need for methods that can be used for kinetic studies of ongoing processes, such as limited proteolysis. Ion-exchange chromatography on a nonporous, compressed agarose matrix was used in the study presented in this paper to monitor papain cleavage of fungal cellulases. This non-porous matrix allows completion of a chromatographic analysis, with baseline resolution, within 30-60 s. Utilizing this very fast chromatographic method one can monitor a proteolysis 'continuously' by repeated chromatographic analysis of the incubation mixture and, if desired, terminate it at the optimal moment. Fractions were also collected for identification by activity assays and analytical SDS-PAGE.
Cellulase↗
Determination of drugs in biosamples at picomolar concentrations using competitive ELISA with electrochemical detection: application to steroids.
A competitive ELISA with electrochemical detection in a flow injection system (FIA) has been developed for determinations of the steroid drug budesonide in biological samples. Plasma samples were cleaned from interfering and cross-reacting compounds by two pretreatment steps consisting of a solid-phase extraction and a liquid chromatography fractionation. The enzyme label was alkaline phosphatase, which was used with p-aminophenyl phosphate (PAPP) as a substrate. The product, p-aminophenol, was detected electrochemically at a glassy carbon electrode at 250 mV (vs Ag/AgCl). The limited stability of both the substrate and the product influenced the performance of the method and had to be taken into account in the procedure by a normalization with time. Budesonide could be quantified in plasma samples down to 10 pM. The major sensitivity-limiting factor was the amperometric background response, probably due to spontaneous hydrolysis of PAPP to p-aminophenol.
Alkaline Phosphatase↗
Duplex ultrasound in patients with suspected aorto-iliac occlusive disease.
Duplex ultrasound scanning was used to localise and classify aorto-iliac occlusive disease. The study included 76 consecutive examinations of 73 patients with signs suggestive of proximal occlusive disease either by history or from traditional non-invasive laboratory investigation. Duplex ultrasound scanning indicated the presence of significant proximal occlusive disease in 70/101 limbs with suspected aorto-iliac disease. In total, 383/393 proximal arterial segments were assessed. A complete evaluation of the aorto-iliac region was possible in 91% of the patients. Duplex scanning was superior to oscillometric amplitude measurements and to CW Doppler examination, especially in patients with concomitant disease of the proximal superficial and deep femoral arteries. Duplex classification of stenoses correlated well with angiographic results obtained in 60 limbs with exact agreement in 194/211 (92%) arterial segments. Three of the patients with disparity between ultrasonography and angiography were investigated with intraarterial pressure measurements demonstrating that these lesions were underestimated by angiography. We conclude that Duplex ultrasound is feasible and accurate in detecting and grading lesions in the aorto-iliac region. This method provides important clinically useful haemodynamic information non-invasively in patients with suspected aorto-iliac occlusive disease.
Adult↗
Quantification of myocardium at risk and detection of reperfusion by dynamic vectorcardiographic ST segment monitoring in a pig occlusion-reperfusion model.
OBJECTIVE: The aim was to investigate whether continuous computerized vectorcardiographic monitoring of absolute spatial ST vector magnitude (ST-VM) and spatial ST change vector magnitude (STC-VM) during coronary occlusion could be used to estimate the size of myocardium at risk; and also to test whether reperfusion could be distinguished from sustained occlusion by continuous monitoring of ST vector alterations. METHODS: Computerised vectorcardiographic monitoring via Frank leads was applied in a closed chest occlusion-reperfusion pig model. Coronary occlusion over 24 h was produced in 20 animals by injecting a 2 mm ball into the left anterior descending coronary artery (n = 7), the right coronary artery (n = 8), and the left circumflex coronary artery (n = 5). Another 31 pigs were reperfused by retraction of the ball after 30 (n = 10), 60 (n = 15), or 90 (n = 6) min of left anterior descending artery occlusion. The extent of the myocardium at risk was measured by autoradiography. RESULTS: Seven animals were excluded. Irrespective of occluded coronary artery the relative parameters STC-VM over the first 30 min of occlusion correlated closely with area at risk, that is, the mean STC-VM between 10 and 30 min of occlusion (r = 0.78 p < 0.001). The absolute parameter ST vector magnitude (ST-VM) did not reflect ischaemia in 16/44 animals and did not correlate significantly with area at risk. The weight of myocardium at risk (MAR) was predictable from STC-VM: MAR weight (measured) = 0.97 x MAR weight (predicted) + 0.26 (g), r = 0.81, p < 0.001. STC-VM decline rate, time to STC-VM plateau, and cumulated sum plots of STC-VM were all able to distinguish reliably between reperfused animals and those with permanent occlusion. A paradoxical increase in STC-VM - "reperfusion peak" - was detected in 17/31 (55%) of the animals. This phenomenon was related to large amount of myocardium at risk or to a long occlusion time. CONCLUSION: Dynamic vectorcardiographic ST monitoring provides adequate estimation of myocardium at risk and enables detection of reperfusion in experimental myocardial ischaemia.
Animals↗
Ischaemia and reperfusion induced transient QRS vector changes: relationship to size of the ischaemic territory.
OBJECTIVE: The aim was to investigate QRS vector changes during the first 30 min of coronary occlusion or the early phase of reperfusion with special reference to location and size of myocardium at risk. METHODS: 24 h experiments were performed in closed chest anaesthetised pigs. QRS vectors were studied by computerised vectorcardiography via Frank leads. Occlusion of the left anterior descending coronary artery followed by reperfusion was induced in 23 pigs and a sustained occlusion in 20 pigs: left anterior descending coronary artery in seven, right coronary artery in eight, and left circumflex coronary artery in five. Myocardium at risk was measured in postmortem autoradiograms. Eight animals were excluded. RESULTS: Four minutes after occlusion, QRS(mean) deviated towards the ischaemic region in 34/35 animals and returned thereafter at varying speeds. In half of the reperfused animals, deviation of QRS vectors towards the ischaemic territory was also observed during the first minutes of reperfusion. A paradoxical increase in QRS vector changes, "reperfusion peak", was recorded during the initial minutes of reperfusion in 12/19 animals. Maximum spatial QRS vector magnitude increased in all right coronary or left circumflex coronary occlusion animals compared to 6/25 in left anterior descending coronary occlusion animals. QRS vector difference, change in spatial QRS vector angle, and maximum change in QRS azimuth 4 min after occlusion correlated significantly with extent of myocardium at risk. CONCLUSIONS: Marked directional and quantitative QRS vector changes, with significant relation to size and location of myocardium at risk, were recorded during the initial minutes of ischaemia. The transient increase in QRS vector changes during the first minutes of reperfusion deserves further exploration as a new indicator of reperfusion.
Animals↗
Glycopyrrolate vs. atropine during anaesthesia for laryngoscopy and bronchoscopy.
As glycopyrrolate has been reported superior to atropine with respect to reduction of salivation, stability of cardiac rate and rhythm, and recovery, a comparison of these properties of the two drugs and placebo was made in 45 patients undergoing direct laryngoscopy and 45 patients undergoing bronchoscopy, in most cases followed by mediastinoscopy. When given i.m. 30 min before anesthesia (midazolam, alfentanil, thiopentone, and suxamethonium), the two test drugs were found to be equally potent regarding the antisialogogic effect. The same increase in heart rate after the test drugs was seen before induction, and during anaesthesia heart rate rose to the same level in the placebo group as the test groups. During anaesthesia, blood pressure was lowest in the atropine group. No differences could be demonstrated with respect to cardiac arrhythmias, possibly due to the small size of the material. The present study gives no reason for preferring either drug, and only the efficacy of both test drugs in controlling airway secretions provides an argument for using any anticholinergic drug when laryngoscopy or bronchoscopy is performed under the conditions of the present study.
Adult↗
Human pulpal response to direct filling gold restorations.
Class V cavities were prepared in 47 caries-free premolars intended to be extracted for orthodontic reasons. A powdered gold filling material, Goldent, which can be hand condensed, was used for direct fillings. The following test groups were used: (A) cavity preparation, no filling, (B) cavity filled with Goldent only, (C) cavity lined with Tubulitec and filled with Goldent, (D) cavity with Goldent filling, sealed with IRM, and (E) positive and negative controls. The teeth were extracted after 1-200 days and the pulpal response was histologically examined. The results revealed that only in Group B, i.e. when the cavity was filled with Goldent, was the risk of a pulpal reaction obvious, although the material per se (Group D) did not influence the pulpal tissue to any serious degree. Probably the Goldent material cannot provide a marginal seal tight enough to prevent microleakage, allowing microorganisms to give rise to pulp damage and inflammation. In those cases where the cavity had been isolated with Tubulitec liner before the gold restoration was made, the pulp was effectively protected from damage caused by microorganisms.
Adolescent↗
Affinity-mediated modification of electrical charge on a cell surface: a new approach to the affinity partitioning of biological particles.
Polylysine has been covalently bound to human transferrin in a 1:1 molar ratio over a disulfide bond that can be easily split by reducing agents such as dithiothreitol. The association constant for the binding of the transferrin-polylysine derivative to transferrin receptors present on rat erythroblasts and the number of binding sites were identical to the corresponding values found for native transferrin. The incubation of the cells with transferrin-polylysine affected the partitioning of erythroblasts in a charge-sensitive aqueous two-phase system containing Dextran and polyethylene glycol. The polylysine part introduced a nonspecific influence on the partitioning that could be eliminated by preincubation of the cells with an excess of sialic acid. The partition ratio, G, of the erythroblasts changed with a factor of 1.9 for each set of 100,000 polylysine chains attached per cell.
Animals↗
Quantification of naturally occurring benzodiazepine-like substances in human breast milk.
The possible occurrence of benzodiazepine-like substances in human breast milk was investigated in 35 healthy, newly delivered women who were known not to be taking benzodiazepines. Maternal blood samples and a sample of breast milk were obtained on the fifth post partum day. A radioreceptor technique (lower limit of detection 1.5 ng/ml; difference between duplicates at various concentrations less than 7%) was used for measuring benzodiazepine-like substances in blood and breast milk (with and without prior extraction). No benzodiazepine-like substances could be demonstrated in any of the blood samples taken from the 35 women. Measurable concentrations of benzodiazepine-like substances were demonstrated in all but 1 of the 35 breast milk samples. The mean concentration of benzodiazepine-like substances for all 35 women was 4.3 +/- 2.3 ng/ml (range 0-9.3 ng/ml) expressed as lorazepam. The corresponding value for extracted breast milk was 2.6 +/- 1.5 ng/ml (range 0-7.0 ng/ml). There was no association between concentrations of benzodiazepine-like substances in breast milk and maternal age, weight, height and body mass or parity, or the sex of the infant and infant birth weight. We suggest that non-detectable amounts of benzodiazepine-like substances in serum are concentrated in the mammillary glands and excreted in a higher concentration in breast milk. It is less likely that the relevant benzodiazepines are produced in the mammillary glands.
Adult↗
Interactions in affinity partition studied using fluorescence spectroscopy.
Fluorescence titration has been used to determine the binding constant and number of binding sites for the textile triazine dye Procion Yellow HE-3G to lactate dehydrogenase from rabbit muscle (E.C. 1.1.1.27). Triazine dye was either free in solution or attached to one of the polymer carriers, polyethylene glycol or dextran. Titrations were performed in solutions of buffer, dextran, and polyethylene glycol. Aqueous two-phase systems composed of polyethylene glycol and dextran were prepared and the binding constant and number of binding sites for ligand polyethylene glycol-Procion Yellow to lactate dehydrogenase were determined in both upper and lower phases of these systems. Affinity partition of lactate dehydrogenase in a PEG-dextran system was also performed using PEG-Procion Yellow as ligand, and partition coefficients of lactate dehydrogenase showed good agreement with theoretical partition coefficients calculated from the binding constant and number of binding sites obtained from fluorescence titration. The advantage of using fluorescence titration to determine affinity of a polymer ligand for a protein is that measurement of binding strength can be made in the actual environment encountered by protein-ligand complex during the purification process.
Algorithms↗
Faecal elimination of lead and cadmium in subjects on a mixed and a lactovegetarian diet.
Faecal elimination of lead and cadmium in 16 subjects who changed from a mixed diet to a lactovegetarian diet has been studied. The faecal weight increased significantly following the change to the vegetarian diet, partly because of increased water content. There was a large inter-individual variation in faecal elimination of lead and cadmium during both the mixed-diet period (range 14 to 118, median 31 micrograms Pb/day; range 4.5 to 21, median 12 micrograms Cd/day) and the vegetarian diet period (range 19 to 136, median 42 micrograms Pb/day; range 6.1 to 24, median 14 micrograms Cd/day). There was a tendency towards increased faecal elimination of lead and cadmium following the change to the vegetarian diet, but the differences were not statistically significant.
Adult↗
Large scale extraction of alpha-lactalbumin and beta-lactoglobulin from bovine whey by precipitation with polyethylene glycol and partitioning in aqueous two-phase systems.
The milk proteins alpha-lactalbumin and beta-lactoglobulin have been isolated from bovine whey by fractional precipitation with polyethylene glycol (PEG) and hydrophobic partitioning in aqueous PEG-hydroxypropylstarch two-phase systems using PEG-bound palmitate as hydrophobic ligand. The possible use of this combination for large scale purification of these whey proteins is discussed.
Animals↗