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Biomedical subjects

C Engström

Publications and source records attributed to C Engström.

47 records · Page 3Linked to original sources
PubMed1982

Alkaline phosphatases in endochondral ossification of rats low in calcium and vitamin D deficient.

Young rats fed a low calcium and vitamin D deficient diet for 2 weeks developed hypocalcemia and increased alkaline phosphatase activity in serum. The serum alkaline phosphatase activity (pNPPase) was found to be of skeletal origin. In accordance, the total non-specific alkaline phosphatase (pNNPase) activity in the microsomal fraction of tibial epiphyseal cartilage and metaphysis increased in the deficiently fed group when compared to the normal group. An increased activity in the microsomal fraction of tibial epiphyseal cartilage and metaphysis was shown both for inorganic pyrophosphatase and total ATP-degrading enzyme activity in the deficient group. This was also found in the presence of R 8231, indicating an increased activity of Ca2+-ATPase, shown to be present in both the epiphyseal plate and the metaphysis. These increased enzyme activities were consistent with the known effects of hypocalcemia and/or parathyroid hormone (PTH) on bone alkaline phosphatase activity. The increase in Ca2+-ATPase might, however, be a direct response to the hypocalcemia present in the deficient animals. Furthermore, the findings in the present study support the view that the same alkaline phosphatase iso-enzyme is present at different calcification loci.

Alkaline Phosphatase↗
PubMed1982

Craniofacial morphology and growth in the rat. Cephalometric analysis of the effects of a low calcium and vitamin D-deficient diet.

The influence of a low calcium and vitamin D-deficient diet on the growth and form of the skull of the growing rat was studied using a cephalometric radiographic technique. First, this technique was used to obtain an intra-individual cephalometric description of the normal growth and form of the skull at different ages during postnatal growth in the rat. It was shown that the methodological error and the biological variation between animals were significantly lower than the registered growth changes, thus demonstrating the suitability of the technique. In the animals fed the low calcium and vitamin D-deficient diet and impaired increase in body weight was found. This diet also caused changes in cranial dimensions, both when the deficient animals were compared with control animals of the same age and with control animals with the same weight. It was concluded that the vitamin D-free and low calcium diet caused a disturbed osteogenesis in growth sites determining the growth and form of the viscerocranium and its relation to the neurocranium.

Animals↗
PubMed1980

Odontoblast metabolism in rats deficient in vitamin D and calcium. IV. Lysosomal and energy metabolic enzymes.

Young rats, fed a low calcium and vitamin D deficient diet for 2 weeks, developed hypocalcemia, an increased activity of serum alkaline phosphatase and an increase in the serum concentration of immunoreactive parathyroid hormone. An increased activity of lactate dehydrogenase and cytochrome oxidase in odontoblasts was found. No shift in the general energy metabolic pathway was found as visualized in the lactate dehydrogenase iso-enzyme pattern. The dominating lactate dehydrogenase isoenzyme in odontoblasts from both the normal and the deficient rats was LDH 1 (H4, LD5), thus indicating primarily an aerobic energy-metabolism Also the activities of the lysosomal enzymes acid phosphatase, cathepsin D and hyaluronidase in the odontoblasts from the deficient animals were increased when compared to the normal animals. No significant change could be demonstrated for beta-glucuronidase and beta-N-acetylglucosaminidase. It was earlier found that this deficient diet caused an increase in odontoblast alkaline phosphatase activities and protein synthesis in vitro. In view of the present findings it might be concluded that the low calcium and vitamin D deficient diet causes a general increase in the odontoblast metabolism. It is not known whether this is due to the increase in parathyroid hormone or if it is a direct effect of the lowered serum calcium concentration.

Acetylglucosaminidase↗
PubMed1980

Effects of local anesthetics on aerobic and anaerobic metabolism of the dental pulp.

Pulps from rat incisor have been dissected out and the respiratory activity in the tissues has been measured in a Gilson respirometer (modified Warburg technique). Local anesthetics lidocain (xylocain) and prilocain (citanest) in concentrations 2.5%, 5%, and 10% have been added to the medium. Effects on the membrane permeability i.e. on the potassium-sodium pump has been studied using incubation at 37 degrees C in 24NaCl. The influx of 24Na has been registered in a scintillation counter. The anaerobic respiratory activity has been studied determining lactate dehydrogenase activity with a spectrophotometric technique. The results show that the concentrations of local anesthetics in the medium of 5% and 10% caused a significantly lower respiratory activity of the cells in the dental pulp. This was not the case in the concentration 2.5%. The isotope studies show a decreased uptake in all concentrations indicating a depression of the potassium-sodium pump activity. The lactate dehydrogenase activity was significantly lower in all concentrations of local anesthetics.

Aerobiosis↗
PubMed1978

Odontoblast metabolism in rats deficient in vitamin D and calcium. III. Protein synthesis in vitro.

Dentinogenically active rat incisor odontoblasts were dissected out from animals fed a low calcium, vitamin D free diet (R 25). Protein synthesis by these cells was studied by means of short-time incubation in an in vitro system in the presence of the radioactive labeled precursors L-leucine, L-fucose and L-proline. A significantly increased leucine and proline incorporation into the protein synthesized was noted in the cells from rats fed the deficient R 25 diet compared with odontoblasts from rats fed an adequate control diet (R 47). No difference between the two groups was found when fucose was utilized as a precursor. The well known increase in predentin width when feeding a rachitogenic diet may thus be explained by an increase in organic matrix synthesis in addition to the possible negative direct effects of lowered serum Ca content. Prior to this study, the behavior of proline as a precursor in the in vitro system was studied. The possibility of separating leucine-labeled proteins synthesized in the in vitro system by means of SDS-polyacrylamide gel electrophoresis was also shown.

Animals↗
PubMed1977

Odontoblast metabolism in rats deficient in vitamin D and calcium I: A histochemical survey.

Different rat diets, deficient in calcium and/or vitamin D, were tested for varying experimental periods to obtain changes in serum calcium values, body weight gain and odontoblast-predentine morphology. One diet, R 25, used during a 14-day period, was found to induce lowered serum calcium values and an increased predentin width in incisor teeth. Rats fed this diet demonstrated an increase in alkaline phosphatase and ATP-splitting enzyme activity in dentinogenically active incisor odontoblasts. No other metabolic changes in these cells were demonstrated by the histochemical methods employed.

Animals↗
PubMed1977

Odontoblast metabolism in rats deficient in vitamin D and calcium. II. Changes in activities of alkaline phosphatases.

Rats were fed a low calcium diet deficient in vitamin D for 14 days. Changes in alkaline phosphatase activities in odontoblasts dissected out from incisor teeth were studied biochemically. A strong increase in pNPP-ase, PPi-ase, total ATP-degradation and Ca2+- ATPase was observed in the deficient animals compared with animals fed a control diet.

Adenosine Triphosphatases↗
PubMed1976

Acid hydrolases in the odontoblast-predentin region of dentinogenically active teeth.

The presence of hyaluronoglucosidase (EC 3.2.1.35; hyaluronidase), beta-N-acetylglucosaminidase (EC 3.2.1.30), exo-1,4-beta-xylosidase (EC 3.2.1.37), and arylsulfatase (EC 3.1.6.1) in dentinogenically active odontoblasts isolated from the rat incisor has been demonstrated by means of biochemical methods. The possible function of these enzymes in relation to the calcification process is discussed.

Acetylglucosaminidase↗