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Biomedical subjects

G Granström

Publications and source records attributed to G Granström.

At least 109 records · Page 6Linked to original sources
PubMed1984

Effect of levamisole on bone resorption in cultured mouse calvaria.

The effects of levamisole (LT), dexamisole (DT), levo-p-bromotetramisole (LBT) and dextro-p-bromotetramisole (DBT) on bone were examined in an organ culture system using calvarial bones from newborn mice. LBT and DBT at concentrations 30 microM and greater and LT and DT at concentrations 100 microM and greater caused a dose-dependent, reversible inhibitory effect on mineral mobilization and matrix degradation. LBT, DBT (100 and 300 microM) as well as LT and DT (greater than or equal to 100 microM) reduced the spontaneous release of beta-glucuronidase without having any marked effect on the release of lactate dehydrogenase (LDH). LT and DT did not influence protein synthesis but LBT and LBT were inhibitory in concentrations at and above 100 microM. Mitotic activity, as assessed by incorporation of [3H]thymidine, was inhibited by LBT and DBT (0.1, 1 mM). LT and LBT caused a stereospecific inhibition of GPase, PPiase and ATPase. It is concluded that tetramisoles are potent, non-stereospecific inhibitors of bone resorption in vitro.

Adenosine Triphosphatases↗
PubMed1984

Further evidence of an intravesicular Ca2+- pump in odontoblasts from rat incisors.

Intracellular vesicles containing alkaline phosphatases were isolated from isolated odontoblasts using several centrifugation techniques, gradient media and filtering procedures. With a combined centrifugation technique using 0.32 M sucrose layered on 1.23 M sucrose, a fraction containing alkaline phosphatases with a 36-40-fold increased specific activity was obtained. This fraction also revealed a high Ca2+-accumulating ability. The vesicle fraction was totally free from mitochondria but to some extent contaminated by lysosomes. Characteristics of Ca2+-uptake were obtained. The Ca2+-uptake was maximal at 37-40 degrees C whereas no Ca2+-accumulated at 4 degrees C. Temperatures above 40 degrees C strongly inhibited Ca2+-uptake. ATP was the most potent stimulator of Ca2+-uptake whereas ITP, GTP, CTP, ADP, PPi and AMP also promoted Ca2+-uptake. Cysteine, EDTA and Triton X-100 were inhibitory to Ca2+-uptake. A correlation between alkaline phosphatases in intracellular vesicles as well as their relation to extracellular matrix vesicles and to the mineralization process is suggested.

Alkaline Phosphatase↗
PubMed1984

Studies on protracted tissue reactions and repair after circulatory and skeletal damage to the rat mandible.

The effect of circulatory and skeletal damage to the distal part of the mandible was studied on young growing rats after interruption of the inferior alveolar artery. The central part of the mandible including the incisor was most vulnerable to circulatory trauma. Maximal damage was seen when the inferior alveolar artery was interrupted combined with bilateral reflection of the mandibular periosteum. The damage produced then was a necrosis of the incisor pulp, odontoblasts and enamel organ and extensive resorption of the centrally-located compact bone. When both sides of the mucoperiosteum remained intact, damage to the main vessels of the mandible did not produce total necrosis of the incisor pulp. Reparative events with production of a fibrous connective tissue of the pulp and osteodentin production were seen. After resorption of sequestered bone was finished, this was replaced by a cell-rich type of bone which also replaced the alveola of those animals which had had their incisors excised. Hypercementosis was seen in the molars after 1 year. No respiratory activity in the incisor pulps was seen after the circulatory damage.

Animals↗
PubMed1983

Influence of bivalent cations, phosphate and complexing substances on inorganic pyrophosphate in the microsomal fraction of isolated rat odontoblasts.

The influence of three diphosphonates, ethane-1-hydroxy 1.1. diphosphonate, methane-diphosphonate and dichloromethane diphosphonate, on inorganic pyrophosphatase (PPiase, E.C. 3.6.1.1.) was investigated. The inhibition by the diphosphonates appeared to be due to their complexation with a bivalent cation, probably Zn2+, which acts as a cofactor for the enzyme. The influence of calcium and inorganic phosphate (Pi) on the PPiase activity was studied in the presence and absence of several complexing substances, including the diphosphonates. Ca2+ alone inhibited the enzyme whereas, in the presence of EDTA, a Ca2+ stimulation of the PPiase was observed which was substrate-dependent and had an optimal activity at a Ca2+:PP4-i ratio of 1:1. There was a small inhibition of the PPiase activity by Pi which was not influenced by the substrate used.

Animals↗
PubMed1983

Effect of different inhibitors on nonspecific alkaline phosphatase in the microsomal fraction from isolated odontoblasts.

In the microsomal fraction isolated from rat incisor odontoblasts, the influence of several inhibitors on p-nitrophenyl phosphatase activity (p-NPPase) was demonstrated at pH 10.3 and compared with the influence at pH 8.8. The inhibiting effect of EDTA on the p-NPPase activity was reversed by equimolar concentrations of Zn2+. The inhibitory effect of three diphosphonates, ethane-1-hydroxydiphosphonate (EHDP), methanediphosphonate (MDP), and dichloromethanediphosphonate (Cl2MDP) was equal to that of a chelating agent. Tetramisole and levamisole exerted an inhibitory effect that was different from the complexing type. L-Cystein, but not L-ascorbic acid, inhibited p-NPPase activity with a maximum inhibitory effect at pH 10.5.

Alkaline Phosphatase↗
PubMed1982

Serologic diagnosis of whooping cough by an enzyme-linked immunosorbent assay using fimbrial hemagglutinin as antigen.

Diagnosis of whooping cough by an enzyme-linked immunosorbent assay (ELISA) that measures serum IgG, IgM, and IgA antibody to the fimbrial hemagglutinin of Bordetella pertussis was compared to isolation from nasopharyngeal swabs in a prospective study. Of 77 patients with upper respiratory tract infections of unknown etiology in which B. pertussis infection could not be excluded on clinical grounds, 26 were culture-positive, including one for Bordetella parapertussis. All 26 patients were positive by ELISA except one asymptomatic erythromycin-treated patient (ELISA sensitivity, 96%). Among culture-negative patients, 24 additional patients were positive by ELISA. Thus, only about one half of the patients with whooping cough were identified by culture under optimal conditions. Positive titers of IgM antibody and/or high titers of IgG antibody in the first serum sample, allowing for a rapid diagnosis, were found only in 26 (53%) of 49 serologically positive patients. By combining culture testing with serology, rapid diagnosis was obtained in 41 (82%) of 50 patients.

Adolescent↗
PubMed1982

Relationship of inorganic pyrophosphatase and para-nitrophenylphosphatase activities of alkaline phosphatase in the microsomal fraction of isolated odontoblasts.

Some properties of inorganic pyrophosphatase (PPiase EC 3.6.1.1.) and para-nitrophenylphosphatase (p-NPPase EC 3.1.3.1) in the microsomal fraction of odontoblasts were investigated. The ratio of Mg2+:p-NPP and Mg2+:PPi for optimal enzyme activities was 1:1. A mutual substrate competition for PPiase and p-NPPase was described. In the presence of 0.1 mM EDTA, Mg2+ alone was not able to reactivate p-NPPase or PPiase. Instead, Zn2+ and Co2+ reactivated the PPiase, indicating they might act as cofactors for the enzyme. Mg2+ increased the PPiase activity, probably because Mg PP2-i was the true substrate for the enzyme. The diphosphonates ethane-1-hydroxy 1,1 diphosphonate (EHDP), methane diphosphonate (MDP) and dichloromethane diphosphonate (Cl2MDP) inhibited the PPiase activity.

4-Nitrophenylphosphatase↗
PubMed1982

Properties of alkaline phosphatases from cellular cementum of rat molars.

The characteristics of nonspecific alkaline phosphatase, (APase, EC 3.1.3.1.) measured as beta-glycerophosphatase (GPase, EC 3.1.3.1.), inorganic pyrophosphatase (PPiase, EC 3.6.1.1.) and adenosine triphosphatase (ATPase, EC 3.6.1.3.) were studied in detail of butanol extracts prepared from rat molar cementum. Mg2+ was not absolutely essential to any of the activities, but at low levels was stimulatory in all cases. Higher concentrations were inhibitory. Ca2+ stimulated ATPase activity weakly at low levels, but was slightly inhibitory to the other enzyme activities. All enzyme activities showed nearly identical sensitivities to heat inactivation and to L-p-bromotetramisole and levamisole, which caused nearly complete inhibition. About 10-15% of the ATPase activity was insensitive to L-p-bromotetramisole and levamisole. The data are consistent with the concept that GPase, PPiase and ATPase activities of cementum to a major part stem from one enzyme, namely nonspecific alkaline phosphatase.

Adenosine Triphosphatases↗
PubMed1982

Early tissue reactions after circulatory and skeletal damage to the mandible of the rat.

Skeletal and circulatory damage in the form of a fracture of the mandible, proximal to the entry of the inferior alveolar artery and other perforantes, alone or combined with unilateral or bilateral mucoperiosteal extirpation, was inflicted on growing young rats. A morphological study of the tissue changes in the bone, dental tissues and soft tissues was performed. Cutting of the nutrient vessels together with extirpation of the periosteum was followed after 10 days by extensive infarction of the incisor pulp, the odontoblasts and the apical part of the enamel organ. The bone was damaged centrally in the mandibular corpus and at the lower border of the ramus, and was partly resorbed during the experimental period. The periodontium showed dilated vessels, but was not damaged. The pulps of the three molars showed numerous dilated vessels but were otherwise not damaged. The oral mucosa, bone marrow, peripheral nerve tissue and peripherally situated bone were not altered. In the animals after fracture alone, oedema of the incisor pulp was present, but infarction did not occur with certainty. A similar bone damage as with mucoperiosteal extirpation was present. The incisor with its dentin and enamel-forming cells was most sensitive to circulatory disturbances due to its central location, while the gingivoperiodontal, mucoperiosteal and midline circulatory systems could nourish the peripheral parts of the mandible. The dependence of the different nutrient systems to bone and dental tissues is discussed.

Alveolar Process↗
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↗
PubMed1981

ATP-dependent uptake of Ca2+ by a microsomal fraction from rat incisor odontoblasts.

Intracellular vesicles containing alkaline phosphatase and Ca2+-ATPase activity were isolated in the microsomal fraction from free-dissected odontoblasts of rat incisors. The microsomal fraction was incubated with 45Ca2+ to study Ca2+ uptake. ATP stimulated Ca2+ uptake, whereas little uptake occurred without ATP. The maximal effect was obtained with 3mM ATP. The ATP-dependent uptake was linear for 2 h. Increasing the pH up to pH 8.2 resulted in an increased uptake. Mg2+ was stimulatory with an optimal effect at a 6mM concentration. Increasing concentrations of Ca2+ up to 100 micrometer enhanced the uptake. A correlation between Ca2+ uptake and Ca2+-ATPase in intracellular vesicles as well as a possible function in the calcification process are discussed.

Animals↗
PubMed1979

Separation of odontoblast Ca2+-ATPase and alkaline phosphatase.

Ca2+-ATPase activity was solubilized, partly purified, and separated from nonspecific alkaline phosphatase activity (APase1) of dentinogenically active rat incisor odontoblasts. Attempts were made to extract the enzymes by various agents, such as Triton X-100, deoxycholate, butanol, EDTA, and buffers of decreasing ionic strength. Solubilization by butanol followed by extraction with low concentrations of EDTA proved to be most effective. Purification and separation were done by molecular sieve chromatography. Ca2+-ATPase showed no activity against p-nitrophenyl phosphate (p-NPP) or inorganic pyrophosphate (PPi) and was unaffected by R 8231 [+/-)-6(m-bromophenyl)-5,6-dihydroimidazo(2,1-b)thiazole oxalate]. It was activated by Ca2+ and Mg2+ ions in equimolar concentrations with the substrate. The enzyme was rapidly inactivated in the solubilized state. An apparent molecular weight of about 18,000 was obtained from molecular sieve data. APase, showing activity against ATP, PPi, and p-NPP, was virtually totally inhibited by R 8231. It was activated by Mg2+ ions but slightly reduced in activity by Ca2+ ions. It had an apparent mol. wt. of 79,000. The results provide direct evidence for earlier suggestions of the existence in hard tissue forming cells of two phosphatases active at alkaline pH.

Alkaline Phosphatase↗
PubMed1978

Ultrastructural localization of alkaline phosphatases in rat incisor odontoblasts.

The localization of alkaline phosphatases in dentinogenically active rat incisor odontoblasts was studied by means of subcellular fractionation and electron microscopical histochemistry. Subcellular fractionation revealed the predominant phosphatase activity to be present in the microsome fraction and to a lesser extent in the mitochondrial fraction. Adenosine triphosphate degrading enzyme activity was determined in the presence or absence of (+/-)-6(m-bromophenyl)-5, 6-dihydroimidazo(le) (2,1-b) thiazole oxalate (R 8231). Before the histochemical study, the effects on phosphatase activities by aldehyde fixation were studied by biochemical assay. A method of fixation for optimal preservation of phosphatase activity is presented. Phosphatase electron microscopic histochemistry was performed by using ATP as a substrate and with or without addition of the inhibitor R 82319 Precipitates were seen in the membranes of vesicles present in the odontoblast process and the Golgi region. When there were signs of insufficient fixation, precipitates were also seen in the outer membranes of mitochondria. No phosphatase activity was seen in the cell membrane. ATP degrading enzyme activities mediated by nonspecific alkaline phosphatase (APase) and Ca2+ -adenosine triphosphatase thus have the same morphological localization. This close association is consistent with earlier biochemical studies.

Adenosine Triphosphatases↗
PubMed1978

Odontoblast alkaline phosphatases and Ca2+ transport.

The same isoenzyme of nonspecific alkaline phosphatase (APase), assayed with p-nitrophenylphosphate (p-NPP), was shown be present in different calcifying tissues, bone, calcifying cartilage, odontoblasts and enamel organ. Indications were also found that the enzymatic degradation of inorganic pyrophosphate (PPi) in calcifying tissues is mediated by APase. By using specific APase inhibitors, it was shown that two enzymes capable of degrading ATP exist. These were characterized in dentinogenically active odontoblasts, and it was concluded that one is the classical APase, the other is a Ca2+ and Mg2+ activated ATPase, named Ca2+-ATPase. The two phosphatases were solubilized from odontoblasts and separated. The localization of APase and Ca2+-ATPase in odontoblasts was investigated by subcellular fractionation and EM histochemistry. Routine methods for fixation were found to almost completely inactivate the enzymes. By using a mild fixation technique that preserved 80% of the enzyme activity, the main localization for both APase and Ca2+-ATPase was found to be in the membranes of intercellular vesicles located in the cell body and odontoblasts process. No activity was found in the cell membranes. It is concluded that there are at least two enzymes able to degrade phosphate compounds at alkaline pH in hard tissue forming cells. One is the nonspecific alkaline phosphatase (APase; EC 3. 1. 3. 1), which is active against p-NPP, PPi, glycerophosphates and ATP among other substrates. The other is a more specific Ca2+-ATPase (EC 3. 6. 1. 3). There seems to be an intimate relation between these two enzymes in the tissue. The function of APase in biological calcification is still obscure. In contrast, the finding of an ATP dependent, intravesicularly directed, transmembranous Ca2+-transport in vesicles derived from the microsomal fraction of odontoblasts may explain the role of Ca2+-ATPase.

Alkaline Phosphatase↗
PubMed1977

A comparative study of alkaline phosphatase in calcifying cartilage, odontoblasts and the enamel organ.

The enzyme alkaline phosphatase (AP) (EC 3.1.3.1) in three different calcification areas was studied by means of a spectrophotometric micro method using p-nitrophenylphosphate as a substrate. Rat maxillary incisor odontoblasts and enamel organ from the zones of matrix formation and maturation and tissue from rabbit metatarsal cartilage were allowed to react with the substrate in glycine-NaOH buffer at room temperature. The reaction was found to be linear for a minimum of 20 min. The pH optima for AP from these tissues were in the pH range of 10.0-10.3. In order to compare AP from the four calcification areas different parameters were studied. Heating at 56 degrees C or 60 degrees C for varying times revealed that the enzymes were almost completely inactivated after 10 min. Mg2+ ions activated the enzymes by about 25% at concentrations of 2.5 mM (enamel organ 1.25 mM); while only higher concentrations of Mg2+ had an inactivating effect, Ca2+ and PO3-4 ions were inactivating at varying concentrations. F- ions showed no effect on AP activity at concentrations below 250 mM (enamel organ 125 mM) but caused inactivation of the enzymes at about 50% at 1 M. EDTA was found to be a very effective AP inactivator at concentrations above 0.06 mM, whereas urea did not noticeably affect the enzyme reactions at concentrations below 1 M. At higher concentrations, inactivation was observed. In order to determine AP localization in the epiphyseal plate successive 40-mum-thick, freeze-sectioned slices were analyzed. The activity was highest nearest the zone of cartilage calcification and decreased towards the reserve cell zone. It was concluded that the same AP isoenzyme is present in these quite different calcification loci.

Alkaline Phosphatase↗
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↗
PubMed1977

ATP-ase activity in the odontoblastic layer of rat incisor. Determination with a radiochemical and a colorimetric method.

The ATP-splitting enzyme activity in odontoblasts isolated from rat incisors has been studied by means of a radiochemical and a colorimetric micromethod. The results with the two methods were virtually identical. The reaction was linear with time for at least 45 min. The pH optimum was found to be 9.8 independently of the ATP concentration. Maximal substrate saturation occurred at a total ATP concentration of 3 mM. Ca2+ and Mg2+ ions activated ATP degradation. F-ions did not affect the activity at low concentrations, whereas higher concentrations were inhibitory. Na+ and ions were slightly inhibitory. Urea inhibited the enzyme activity at concentrations above 1.5 M, while EDTA and EGTA were strong inhibitors at very low concentrations. When incubating in the presence of low concentrations of specific inhibitors for nonspecific alkaline phosphatase, levamisole and R8231, about 20% ATP degrading enzyme activity remained. In conclusion it is suggested that there are at least two ATP degrading phosphatases active at alkaline pH.

Adenosine Triphosphatases↗