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Biomedical subjects

L Lindqvist

Publications and source records attributed to L Lindqvist.

At least 73 records · Page 4Linked to original sources
PubMed1982

Determination of salivary ABH-blood group antigens by rocket affinoelectrophoresis.

A rocket affinoelectrophoretic assay system was used to detect and quantify the human salivary ABH-blood group antigens of 155 individuals. In this system blood group antigens precipitated as rockets in agarose gels containing different lectins, with the rocket height being correlated to the antigen concentration. This technique was compared with the classical hemagglutination inhibition method for determination of salivary blood group antigens, and it was demonstrated that salivary A, B and H blood group antigens were detected with the lectins from helix pomatia, Bandeiraea simplicifolia and Ulex europeus, respectively. The technique was rapid and sensitive, with a detection limit of 0.1 microliters saliva. This technique can also be used for determination of blood group antigens derived from other body fluids, tissues and cells.

ABO Blood-Group System↗
PubMed1980

Transient haem-globin interactions in photodeligated carboxyhaemoglobin and subunits.

Although the fixation of ligand to haemoglobin (Hb) is known to be accompanied by changes in protein conformation regulating the oxygen exchange in blood, the mechanism triggering these changes remains undecided. We now report a dynamic approach to this problem using results obtained in a nanosecond laser photolysis study of carboxyhaemoglobin (HbCO) and its isolated subunits. The study is based on our previous observation of a structural evolution of free Hb after photodeligation, manifested through slight variations of the protein spectrum in the microsecond range. It is now found that the isolated subunits also show this behaviour. The duration of the spectral evolution is approximately 2 microseconds for the three proteins and the activation energy of the process approximately 9 kcal mol-1. The spectral evolution is attributed to local conformation changes at the haem region, occurring during the structural relaxation of the freshly deliganded protein. The results for the isolated chains show that such changes exist even in the absence of the R-T transition.

Carboxyhemoglobin↗
PubMed1980

In vivo and in vitro studies of inhibitory effects of restorative dental materials on salivary esterases.

The influence of 18 dental materials on the activity of esterases isolated from human whole saliva has been studied. Eugenol on its own was a strong competitive inhibitor of the esterases II-2a (Ki = 3.3/10(-5) M) and II-2b (Ki = 4.7/10(-6) M). Except for Luralite all the materials that contained eugenol as one of the components (IRM, Nobetec and Opotow) were noncompetitive inhibitors. Additional in vitro inhibitors were: Adaptic, Aspa, Coe-pack and the amalgam ANA 68. Treatment with Nobetec packs in vivo resulted in a decrease activity of whole saliva.

Dental Materials↗
PubMed1980

Eugenol: liberation from dental materials and effect on human diploid fibroblast cells.

The amount of eugenol (4-allyl-2-methoxyphenol) released from four different dental materials immersed in phosphate buffer was measured by gas liquid chromatography. Maximal release of eugenol from zinc oxide-eugenol cement (ZOE) and IRM was attained within 5 h and corresponded to 5% and 4%, respectively, of the total amount of eugenol in each material. Both the rates and total amounts of eugenol released from Nobetec and Opotow were lower than for ZOE and IRM. Eugenol (0.67 mM) applied to growing cultures of human diploid fibroblasts reduced the number of cells recovered to a value which was 4% of that found for control cultures which grew to form monolayers. Confluent monolayers of 3H-uridine labeled cell cultures which were incubated for 1 h in the presence of 4 mM eugenol lost approximately 100% of this cytoplasmic label, indicating total cell death.

Cells, Cultured↗
PubMed1980

Purification of glycoside hydrolases from Bacteroides fragilis.

Six glycoside hydrolases in the culture medium of Bacteroides fragilis--alpha-glucosidase, beta-glucosidase, alpha-galactosidase, beta-galactosidase, beta-N-acetylglucosaminidase, and alpha-L-fucosidase-were systematically purified by ammonium sulfate precipitation, gel filtration chromatography, and density gradient isoelectric focusing. The isoelectric focusing resolved the glycosidases into distinct, well-separated fractions and revealed three differently charged forms of beta-N-acetylglucosaminidase and of alpha-L-fucosidase. Furthermore, alpha-glucosidase and beta-N-acetylglucosaminidase were shown to possess dual affinities for the respective galactoside substrates, and beta-galactosidase also hydrolyzed beta-D-fucoside. alpha-Glucosidase was purified to homogeneity, as indicated by a thin-layer isoelectric focusing zymogram technique. The glycosidases, with exception of beta-glucosidase and the acid alpha-L-fucosidase, were each separated from other glycosidic activities to 99%. The molecular weights varied between 58,000 and 125,000. The pH optima ranged from 4.8 to 6.9.

Acetylglucosaminidase↗
PubMed1980

Effects of phenoxymethylpenicillin, clindamycin and tinidazole on the anaerobic oral, throat and colon flora in man.

Capsules of phenoxymethylpenicillin were given orally to ten subjects in doses of 800 mg twice daily for 7 days. Saliva, throat and faecal specimens were taken over a 29-day period and bacterial cultivations were carried out. No changes in the normal flora of the saliva, throat or faeces were noted during this period. Clindamycin was given orally to ten other subjects in doses of 150 mg, four times per day for 7 days. No changes in the aerobic flora of the saliva and throat were observed while a significant decrease in the number of anaerobic bacteria occurred. Overgrowth of clostridia was seen in two cases. Pronounced changes in the faecal flora occurred. Among the aerobic bacteria, enterococci proliferated, and among the anaerobic bacteria significant decreases in the numbers of cocci and gram-negative rods were seen. In four subjects the number of clostridia increased significantly. Tinidazole was given orally to ten other subjects in doses of 150 mg every 12 hours for 7 days. Slight changes were noted in the anaerobic flora of the saliva while no differences were seen for the faecal flora.

Adult↗
PubMed1977

Origin of esterases in human whole saliva.

Whole saliva of 59 healthy persons was used for determination of esterase activity. The pattern of esterase was studied by means of isoelectrofocusing on thin-layer acrylamide gels. The esterases found in whole saliva are suggested to be derived from the cells of the tissue in the oral cavity. This origin is indicated (e.g.) by comparison between isolectrophoretic esterase patterns of whole saliva, submandibular saliva, gingival biopsy and fibroblast culture. Antisera against partially purified saliva esterases were produced in rabbits. These sera, used in immunoelectro-osmophoresis, gave esterase-active immunoprecipitate against whole saliva, the water-soluble materials of disrupted gingival biopsy and fibroblast culture, but not against the material of the bacteria, Streptococcus sanguis, Strptococcus mutans, Streptococcus mitis, Actinomyces viscosus and Lactobacillus fermentum.

Amylases↗
PubMed1975

Porphyrin triplet state probing the diffusion of oxygen in hemoglobin.

Laser photolysis study of porphyrin-globin shows that the triplet state of the porphyrin is detectable by its light absorption and that it can be used to determine the rate of penetration of oxygen into the hemoglobin pocket in which the porphyrin is embedded. The oxygen penetration rate does not determine the binding rate of oxygen to iron in hemoglobin.

Chemical Phenomena↗
PubMed1975

Esterases in human saliva.

A sensitive method for quantitative determination of esterase activity has been applied to human saliva and used for substrate and inhibitor studies. By means of gel isoelectrofocusing the whole saliva esterases were divided into two main groups, each resolved into several bands. Comparison of isoelectrophoretic zymograms of whole, submandibular and parotid saliva indicates that one of the groups originates from the submandibular fluid. With the aid of gel filtration and ion-exchange chromatography the saliva esterases were partially separated and purified. The classification of the main saliva esterases as carboxylesterases (EC 3.1.1.1) is discussed in terms of their substrate and inhibitor properties.

Acetazolamide↗
PubMed1974

The kinetics of conformational changes in hemoglobin, studied by laser photolysis.

Photolysis of carbon monoxide and oxygen derivatives of hemoglobin by a short laser pulse produces a transient species that rapidly decays to normal deoxyhemoglobin. The effect, which is also observed on single chain proteins and on noncooperative aggregated forms, has been interpreted as corresponding to structural changes in the heme pocket on ligand dissociation. The decay of the transient species follows first-order kinetics with constants ranging from 0.8 to 1.8 x 10(7) sec(-1). In cooperative hemoglobins, the kinetic constants are pH-dependent, though remaining first- or pseudo first-order at all wavelengths. This shows the close linkage of tertiary and quaternary structure changes in normal hemoglobin.

Animals↗