Biomedical subjects

E Solheim

Publications and source records attributed to E Solheim.

At least 37 records · Page 2Linked to original sources

PubMed1995

Ethylene oxide gas sterilization does not reduce the osteoinductive potential of demineralized bone in rats.

It has been shown that different sterilization procedures of demineralized bone may influence its osteoinductive properties. The aim of this study was to evaluate the effect of ethylene oxide sterilization for 1, 3, and 6 hours on the osteoinductive potential of allogeneic demineralized bone implanted heterotopically in rats. Sixty male Wistar rats were randomly assigned to one of four groups, A through D, and four demineralized bone chips (2.8 mg) were implanted in a pouch created between the right oblique abdominal muscles in each animal. In Group A, the demineralized bone was implanted without prior sterilization of the material, whereas the demineralized bone implanted in Groups B, C, and D had been sterilized in ethylene oxide gas for 1, 3, or 6 hours, respectively, and aerated for 48 hours. At 4 weeks postoperatively, bone formation was evaluated quantitatively by strontium 85 uptake and qualitatively by light microscopy of histological sections. One-way analyses of variance at the 0.05 level revealed no significant difference in strontium 85 uptake of the different groups, and no qualitative differences in osteoinduction could be detected by light microscopy. Ossicles consisting of bone and bone marrow were seen in the recovered implants of all groups.

Analysis of Variance↗

PubMed1995

Leaching from denture base materials in vitro.

Specimens made from denture base materials were leached in Ringer solution and in ethanol. The specimens comprised a heat-cured product processed in two different ways and two cold-cured materials. The organic compounds leaching from the specimens to the solutions were separated, identified, and quantified by a combined gas-chromatography and gas-chromatography/mass-spectrometry technique. Additives and degradation products, possibly made by free radical reactions, were released from the denture base materials. In Ringer solution only phthalates could be quantified. In ethanol solvent, biphenyl, dibutyl phthalate, dicyclohexyl phthalate, phenyl benzoate, and phenyl salicylate were quantified. In addition, copper was found in the ethanol solvent from one of the denture base materials. The amount of leachable organic compounds varies among different materials. Processing temperature influences the initial amount of leachable compounds.

Benzoates↗

PubMed1995

Fatty acid composition of palatal tissue from denture stomatitis patients.

Palatal biopsy specimens were obtained from patients with denture stomatitis. The fatty acids were extracted from the tissue, then separated, identified, and quantified by a gas-chromatographic technique. The sensitivity of this method enabled analyses of specimens with a wet weight of less than 1 mg. The concentration of the fatty acids C16:1 (n-7) and C24:1 (n-9) differed significantly between samples from hyperplastic and clinically healthy tissue in the denture stomatitis patients. By comparing specimens from denture stomatitis patients and non-denture subjects, the concentration of seven fatty acids, two saturated and five unsaturated, was found to be significantly different. A multivariate data-analytical method distinguished between the fatty acid composition in specimens from denture stomatitis patients and from non-denture subjects.

Adolescent↗

PubMed1995

Biologic testing of leachable aromatic compounds from denture base materials.

The aromatic compounds phenyl benzoate (PB), phenyl salicylate (PS), and biphenyl (BP), which have previously been found to leach from poly(methyl methacrylate) denture base materials, were tested for cytotoxicity and biologic effects by L929 cells in culture. The octanol-water partition coefficient (log P(ow), a descriptor for the lipophilicity, was determined for the compounds. Cytotoxicity was evaluated by total cell growth and the plating efficiency test, and biologic effects by the total fatty acid composition of L929 cells. The commonly used tests, total cell growth and plating efficiency, did not show any significant changes of the cells due to the compounds. On the other hand, BP and PS, in particular, induced changes in the total fatty acid composition of L929 cells. The problem of bioavailability of aromatic compounds in cell culture assays and the relation to lipophilicity was addressed.

Animals↗

PubMed1995

Anatomical and functional results five years after remanipulated Colles' fractures.

During 1988 we recorded all Colles' fractures (n = 530) in a prospective study in the city of Bergen. According to defined criteria, the fractures were treated by immobilisation in plaster cast with or without reduction; reduction and immobilisation by a Hoffman external fixation device; or open reduction and internal fixation. Included in the present study were 26 patients with secondary displacement after immobilisation in a plaster cast (8% of the reduced fractures). The fractures were remanipulated and splinted in a new cast for four more weeks. The patients were followed up five years after the fracture, and underwent subjective, radiographic, and functional evaluation. The anatomical end result was significantly improved compared with the initial deformity. The dorsal angulation improved significantly compared with the "slipped' position, whereas the radial length did not. The functional end result was excellent or good in 20 patients (77%). The total movement in all directions was correlated negatively with ulna plus, and the grip strength correlated negatively with the degree of osteoarthrosis. There were no other significant linear relationships between anatomical and functional variables. Total pronation and supination correlated with the initial radial length and dorsal angulation, and the total movement in all directions correlated with the initial radial length.

Casts, Surgical↗

PubMed1994

Prediction of secondary displacement in Colles' fracture.

In a prospective study, 645 consecutive Colles' fractures treated conservatively were followed until union. The fractures subsequently lost some of their manipulated position during the immobilization period. However, the anatomical end result was significantly improved compared with the initial deformity. The mean shortening of the radius during plaster-cast treatment was 3 mm, and the mean increase of dorsal angulation was 7 degrees. Multiple regression analyses showed that initial dorsal angulation, age, and Older type were important predictor variables for the end result of dorsal angulation. Initial radial length, age and initial dorsal angulation were of importance for the end result of radial length. The strongest linear relationship was found between the end result of radial length and the initial radial length (r = 0.67). This may indicate that the patients who will malunite with radial shortening are those with significant radial axial shortening at the initial presentation. Thus, these patients should be treated with a more stable fixation device.

Bone Malalignment↗

PubMed1994

Revascularization of calvarial, mandibular, tibial, and iliac bone grafts in rats.

Some studies have suggested that membranous bone grafts undergo less resorption than endochondral grafts, and faster revascularization of the former has been proposed as the explanation. We studied fresh syngeneic full-thickness bone grafts from calvaria, mandibula, tibia diaphysis, and iliac bone implanted in the back muscles of young Lewis rats. As a measure of the quantity of cancellous bone in grafts before implantation, the ratio of the total area of soft-tissue spaces to the total area of the graft was measured histomorphometrically. Revascularization in grafts 3 weeks postoperatively was evaluated by deposit of 141Ce-labeled microspheres. Both the quantity of cancellous bone (before implantation) and the revascularization (3 weeks postoperatively) were greater in the mandibular and iliac bone grafts than in the calvarial and tibia diaphyseal grafts. The results suggest that the anatomical area of harvest of bone graft is important regarding early revascularization, but the results do not support the theory that different embryological mode of development is the cause since mandibula (high 141Ce index) and calvaria (low 141Ce index) are of membranous origin and iliac bone (high 141Ce index) and tibia (low 141Ce index) are of endochondral origin. The difference in revascularization between the different grafts may be explained by differences in quantity of cancellous bone since cancellous bone is revascularized faster than cortical bone.

Animals↗

PubMed1994

Effect of storage on osteoinductive properties of demineralized bone in rats.

A requirement for the clinical use of demineralized bone is the possibility of storing the material without loss of its osteoinductive properties. Seventy-five 8-week-old male Wistar rats were randomly assigned to one of five groups of 15 rats each. Lyophilized demineralized allogeneic bone was prepared and implanted in the abdominal muscle either without prior storage (control group) or after storage for 9 or 14 months at -70 degrees C or 4 degrees C (four experimental groups). Bone formation in the implants was evaluated quantitatively 4 weeks postoperatively by measuring the strontium 85 uptake of the recovered implants. Storage for 9 months at both temperatures did not affect the osteoinduction, whereas storage for 14 months at both temperatures led to a statistically significant decrease in osteoinduction.

Animals↗

PubMed1994

Leaching of additives and degradation products from cold-cured orthodontic resins.

Unstimulated saliva was collected from orthodontic patients and subjected to combined gas-chromatography and gas-chromatography/mass-spectrometry analyses. Saliva was collected before insertion of removable orthodontic appliances made of cold-cured resins. Saliva was then collected 1-2 months after insertion of the appliances and 1 week after they had been removed. Phenyl benzoate (PB) and phenyl salicylate (PS) were identified in pooled saliva samples from patients wearing the appliances. Biphenyl and 2-methoxy-4-hydroxy-benzophenone in addition to PB and PS were identified in a study with in vitro specimens made of orthodontic resin. The leaching of compounds from these test specimens processed by a powdering technique and a pre-mix technique was compared.

Biphenyl Compounds↗

PubMed1993

Leaching of organic additives from dentures in vivo.

Samples of saliva were collected from subjects with dentures. These samples were collected both before the dentures were replaced and 1 week after the subjects had received their new dentures. Dibutylphthalate and phenyl benzoate were detected in the saliva samples with a gas-chromatography and a gas-chromatography/mass-spectrometry technique. We also quantified the dibutylphthalate in the saliva. In addition, in an in vitro study, we identified biphenyl leached from heat-cured denture base polymer plates. Our study suggests that subjects with dentures have higher contents of the above organic substances in saliva than subjects without dentures and that organic additives leach from new heat-cured dentures.

Adult↗

PubMed1993

Pathological hepatic accumulation of long-chain n-alkanes ("paraffin liver") in cows (Harbitz and Fölling, 1940). An overlooked discovery. Description of lesions and identification of alkanes.

About 50 years ago crystalline deposits of a substance representing approximately 7 per cent wet tissue weight and believed to be hentriacontane or a mixture of similar long-chain n-alkanes (30-34 carbon atoms) were detected in two discoloured and swollen cow livers. Stored purified extracts from these livers were recently reanalysed using gas chromatography and mass spectrometry. They were found to contain about equal amounts of nonacosane and hentriacontane with a small admixture of tritriacontane and other long carbon-chain alkanes. On the basis of histological findings, five additional cases of "paraffin liver" in cows have been recorded. In the discussion comparison is made with the only known case of a similar disorder in a human, visceral accumulation of the same three alkanes as in the cows, which was recently described in the literature. Concerning the origin of the deposits, importance is given to the fact that the long-chain alkanes with odd carbon numbers identified both in cattle and man predominate in the cuticular waxes of many dietary plants. The very large quantities of the abnormal substance in the cow livers indicate low toxicity, and evidently accumulation over long periods of time.

Alkanes↗

PubMed1992

Effect of local hemostatics on bone induction in rats: a comparative study of bone wax, fibrin-collagen paste, and bioerodible polyorthoester with and without gentamicin.

Local hemostatics for osseous tissue should preferably be absorbable and biocompatible and should not inhibit osteogenesis. The tissue response and effect on demineralized bone-induced heterotopic osteogenesis in the abdominal muscle of 120 male Wistar rats by different local hemostatics were evaluated by light microscopy and 85Sr uptake analyses. Non-absorbable bone wax of 88% beeswax and absorbable bovine fibrin-collagen paste both significantly inhibited osteoinduction, whereas a bioerodible polyorthoester drug delivery system with or without 4% gentamicin did not. Bone wax was not absorbed and induced a chronic foreign body reaction. Fibrin-collagen paste induced less inflammation with numerous monocytes and macrophages with engulfed material. Bioerodible polyorthoester caused a very moderate tissue reaction and was mostly resorbed at week 4.

Absorption↗

PubMed1992

Bone induction by composites of bioresorbable carriers and demineralized bone in rats: a comparative study of fibrin-collagen paste, fibrin sealant, and polyorthoester with gentamicin.

Host tissue response and heterotopic osteoinduction by composites of demineralized bone matrix and three different substances used as bioresorbable carriers implanted in the abdominal muscles were evaluated by strontium 85 uptake and histology 4 weeks postoperatively in 60 male Wistar rats. Both fibrin-collagen paste and fibrin sealant inhibited bone induction and produced a chronic inflammation; part of the fibrin-collagen paste was still present at 4 weeks. Polyorthoester with gentamicin was almost completely absorbed, induced minimal tissue reaction, and did not inhibit osteoinduction.

Absorption↗

PubMed1992

Fatty acids of healthy and periodontally diseased root substance in human teeth.

In this comparative study, samples of root substance from healthy and periodontally diseased human teeth were analyzed for fatty acids by means of a gas-chromatographic technique. The sample preparation procedure allowed specimens from individual teeth to be analyzed. The content of the fatty acids C16:0, C16:1, C18:0, and C18:1 in the superficial layer of the periodontally diseased teeth was significantly higher than that of healthy teeth. In the inner layer, there was no such difference. Four different 3-hydroxy fatty acids (3-OH C14:0, 3-OH C15:0, 3-OH C16:0, and 3-OH C17:0) were identified by combined gas-chromatography/mass-spectrometry in the tooth substance of periodontally diseased teeth. This indicates the presence of lipid A, which is the toxic component of bacterial lipopolysaccharides.

Chromatography, Gas↗

PubMed1992

Comparison of histomorphometry and 85Sr uptake in induced heterotopic bone in rats.

Heterotopic bone formation in the abdominal muscle of 45 male 8-week-old Wistar rats induced by implantation of 5, 10, or 15 mg demineralized bone (DBM) powder was evaluated at 4 weeks by 85Sr uptake of the implants and area histomorphometry of the induced bone. Two indices of 85Sr uptake were calculated: the osteogenic index [(counts/min/mg implant)/(counts/min/mg os ilium)] and an index that we have called the osteoquantum index in which the weight of the implant is disregarded [(counts/min implant)/(counts/min/mg os ilium)]. The osteoquantum index showed a linear relationship to the area of the induced bone with a correlation coefficient (r) of 0.90. Only weak linear relationships were found between the osteogenic index and the area of the bone (r = 0.32) and between the osteogenic index and the osteoquantum index (r = 0.33). The osteoquantum index and the area of the induced bone both increased with increasing mass of implanted DBM, whereas the osteogenic index did not change.

Analysis of Variance↗

PubMed1992

Regeneration of calvarial defects by a composite of bioerodible polyorthoester and demineralized bone in rats.

A study was performed to evaluate regeneration of defects in rat calvaria either unfilled or filled with a bioerodible polyorthoester only, demineralized bone only, or a composite of both. At 4 weeks, histological and radiographic studies showed that defects filled with a composite of bioerodible polyorthoester and demineralized bone or demineralized bone alone were bridged by bone. Unfilled defects or defects filled with polyorthoester only did not heal. The polyorthoester caused slight inflammation that subsided by 3 weeks, and only traces of the filler could be detected at 4 weeks. The polyorthoester provided local hemostasis when used either alone or in composites with demineralized bone. The composite implant was moldable, easily contoured, and technically easier to use than demineralized bone alone.

Animals↗

PubMed1992

Inhibition of heterotopic osteogenesis in rats by a new bioerodible system for local delivery of indomethacin.

A study was done to evaluate the effect of a system for the local delivery of indomethacin on demineralized bone-induced formation of heterotopic bone in the abdominal muscles of rats. Two separate investigations were conducted on a total of forty-eight Wistar rats. In both series, two types of implants were used: polyorthoester and demineralized bone (Group A, the control group) and polyorthoester with 5 per cent indomethacin and demineralized bone (Group B, the experimental group). In the first series, host-tissue responses and osteoinduction were evaluated histologically at two, three, and four weeks after the implantation. In the second series, the formation of bone was quantified on the basis of uptake of 85Sr at four weeks after the implantation. The polyorthoester system for the local delivery of indomethacin significantly inhibited demineralized bone-induced heterotopic formation of bone, as demonstrated by light microscopy and by uptake of 85Sr. The polyorthoester, with or without the drug, caused little tissue reaction and was resorbed almost completely at four weeks.

Abdominal Muscles↗

PubMed1992

The effect of a composite of polyorthoester and demineralized bone on the healing of large segmental defects of the radius in rats.

The effect of a composite of demineralized bone mixed with polyorthoester on the healing of large segmental defects in the rat radius was studied. Sixty male Wistar rats were divided into four groups, A through D, and an osteoperiosteal diaphyseal defect of 50 per cent of the length of the bone was made in the right radius of each rat. In Group A, the defect was filled with polyorthoester and demineralized bone; in Group B, demineralized bone; and in Group C, polyorthoester. No material was implanted in the defects in the Group-D rats. The rats were killed fifty days postoperatively. The formation of bone in the defects was quantified with computer-assisted measurements of the area on radiographs. The host-tissue response was evaluated with light microscopy. Defects that had been filled with the composite of polyorthoester and demineralized bone or with demineralized bone alone showed regeneration of bone corresponding to 93.6 and 77.6 per cent of the area of the defect, respectively. Defects that had no implant or that had been filled with polyorthoester alone showed significantly less formation of bone. No inflammation was seen with light microscopy, and only traces of the polyorthoester could be detected in the defects that had been filled with the composite or with polyorthoester alone.

Animals↗