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Biomedical subjects

A Linde

Publications and source records attributed to A Linde.

At least 307 records · Page 17Linked to original sources
PubMed1975

The presence of alkaline phosphatase in the subchondral bone of the medial tibial condyle in the normal state and in osteoarthritis and rheumatoid arthritis.

A study has been carried out on the alkaline phosphatase activity in trabecular bone in the normal state, rheumatoid arthritis and osteoarthritis. Samples were taken from the subchondral bone of the medial tibial condyle in all cases. The reason for this study was to investigate whether changes in rheumatoid bone like trabecular microfractures and healing reactions were parallelled by a mineralization process which could be demonstrated by an increased alkaline phosphatase activity and compared to that in osteoarthritic and normal bone. This investigation disclosed that the alkaline phosphatase activity in rheumatoid bone did not differ much from either osteoarthritis or normal bone.

Adult↗
PubMed1975

Scanning electron microscopic studies of the rat incisor odontoblastema.

A scanning electron microscopic technique was used to investigate the surface structure of dentinogenically active odontoblasts. Thin pieces of rat incisors were fixed, rapidly frozen, freezedried at minus 70 degrees C and fractured to expose new surfaces prior to examination in the SEM. Differences in the appearance of odontoblastic cell surfaces were seen, with the most extensive ridge formations at the distal part of the sides of the odontoblasts. The predentine area displayed a spongy structure which contrasted to the compact appearance of dentine. Results are discussed in relation to previous studies at the light microscopic and transmission electron miscroscopic levels.

Animals↗
PubMed1975

Leucine and fucose incorporation into odontoblast protein.

Odontoblasts isolated from rat incisors were incubated in vitro in the presence of tritiated leucine or fucose, and the amount of precursor incorporated into TCA-recipitated proteins was determined. The effect on precursor incorporation of varying the total precursor concentration was examined. The incorporation of leucine and fucose into TCA-precipitated proteins was found to be linear with time for at least 90 min. Inhibition studies with puromycin, cycloheximide and chloramphenicol demonstrated the presence of odontoblastic protein synthesis. One hour after in vivo administration of triated leucine the highest specific activity of odontoblast-predentin protein material was noted the corresponding maximum for pulp proteins was found to occur after 30 min. The in vivo incorporation of triated fucose was maximal after 4 h in both odontoblasts and pulp tissue.

Animals↗
PubMed1975

Determination of inorganic pyrophosphatase in rat odontoblast layer by a radiochemical method.

The enzyme inorganic pyrophosphatase (PPiase, EC 3.6.1.1) from the odontoblastic layer of rat incisors has been studied by means of a radiochemical micromethod. The enzyme was incubated with 32P-pyrophosphate in tris-HCl buffer at 37 degrees C. The reaction was linear with time for at least 45 min, and the pH optimum was found to be 8.8, independent of the amount of pyrophosphate present. Heating the enzyme at 56 degrees C inhibited the enzyme activity rapidly, Mg2+ ions activated the enzyme by 15% at an ion concentration of 4 mM, while higher concentrations were inhibitory. Ca2+ ions and PO43-ions inhibited the enzyme at all concentrations. F- ions did not affect the PPiase at concentrations below 8 mM, whereas higher concentrations had an inhibiting effect. Urea was found to inhibit the enzyme at concentrations above 1.5 M, while EDTA was a strong inhibitor at very low concentrations. The characteristics of PPiase agree well with the properties of the enzyme nonspecific alkaline phosphatase (EC 3.1.3.1.) studied earlier.

Animals↗
PubMed1975

Inhibition studies of alkaline phosphatase in hard tissue-forming cells.

The effects of the alkaline phosphatase inhibitors levamisole and R 8231 on p-nitro-phenylphosphatase, inorganic pyrophosphatase and adenosine triphosphatase (ATPase) activities in dentingenically active odontoblasts were studied. The p-nitrophenylphosphatase and inorganic pyrophosphatase activities were inhibited, while 40% of the ATP-splitting enzyme activity remained under the assay condition used. This finding, togeather with earlier studies, indicates that at least two different phosphatase are active at alkaline pH in hard tissue-forming cells; on nonspecific alkaline phosphatase and one specific ATPase. The ATPase activity is uninfluenced by ouabain and ruthenium red and is activated by Ca-2+ ions.

4-Nitrophenylphosphatase↗
PubMed1975

Inorganic pyrophosphatase in isolated enamel organ and odontoblasts from the rat incisor.

The inorganic pyrophosphatase (PPiase) activity was determined by a colorimetric method in the odontoblasts and the parts of the enamel organ related to enamel matrix formation and enamel maturation. The effects on PPi hydrolysis by EDTA, R 8231, urea and heat treatment were found to be almost identical to those reported for nonspecific alkaline phosphatase (APase) in the same tissues. The Mg2+ activation curve for PPiase was also similar. Like those of APase, these characteristics of PPiase activity were identical in the three locations studied. It is suggested that the close similarity in the properties of PPiase and APase is due to activity of the same enzyme, a concept which is in agreement with recent biochemical and histochemical studies of calcification.

Animals↗
PubMed1973

Screening plate method for detection of bacterial beta-glucuronidase.

For screening tests of bacterial beta-glucuronidase (EC 3.2.1.31) activity an agar plate (MUG plate) containing the enzyme substrate, 4-methylumbelliferyl-beta-D-glucuronide, was developed. In the presence of beta-glucuronidase, the strongly fluorescent 4-methylumbelliferone, which can be detected by ultraviolet light, was liberated. For tests of fastidious bacteria, the MUG-plate was enriched with supplements containing heat-labile growth factors without influencing the reaction. The plate was found to be suitable for screening tests. The sensitivity of the MUG-plate was determined by means of fluorimetric method. With the present method, beta-glucuronidase activities were demonstrated in some well-known beta-glucuronidae-producing microorganisms as well as in Bacteroides and Corynebacterium spp.

Agar↗