Biomedical subjects

E Solheim

Publications and source records attributed to E Solheim.

At least 19 recordsLinked to original sources

PubMed2001

Revascularisation of fresh compared with demineralised bone grafts in rats.

Revascularisation of bone grafts is influenced by both the anatomical origin and the pre-implantation processing of the graft. We investigated the revascularisation by entrapment of 141Ce (cerium)-labelled microspheres in large, fresh and demineralised syngeneic grafts of predominantly cancellous (iliac bone) or cortical (tibial diaphysis) bone three weeks after heterotopic implantation in rats. The mean (SD) 141Ce deposition index (counts per minute (cpm) of mg recovered implant/cpm of mg host iliac bone) was higher in fresh iliac bone grafts, 0.98 (0.46) compared to that of demineralised iliac bone, 0.32 (0.20), p < 0.001, and fresh tibial bone grafts, 0.51 (0.27), p = 0.007. We found no significant difference in the mean 141Ce deposition index between fresh tibial bone grafts and demineralised tibial bone grafts, 0.35 (0.42), p = 0.4, or between demineralised tibial grafts and demineralised iliac bone grafts, p = 0.8. The results suggest that whereas fresh cancellous grafts are revascularised more completely than fresh cortical grafts, there is no difference in the revascularisation of demineralised cancellous and cortical grafts. In addition, fresh cancellous bone is revascularised more completely than demineralised cancellous bone, whereas there is no difference between fresh and demineralised cortical bone.

Animals↗

PubMed2001

The relationship between revascularisation and osteogenesis in fresh or demineralised bone grafts.

Bone formation generally depends on adequate blood flow. Failure of bone grafts has been attributed to delayed revascularisation of the graft. We compared the relationship between revascularisation and osteogenesis, evaluated as entrapment of (141)Ce-labelled microspheres and uptake of (85)Sr, respectively, in fresh or demineralised syngeneic bone grafts 3 weeks after heterotopic implantation in rats. Whereas a moderately high linear correlation between (85)Sr and (141)Ce radioactivity was found both in the (intact) host iliac bone (r = 0.75, p = 0.0001) and implanted fresh syngeneic grafts (r = 0.50, p = 0.001), no correlation could be demonstrated in demineralised grafts (r = 0.09, p = 0.6). The results may indicate differences in the mechanisms of vascularisation and osteogenesis in the grafts used fresh or after demineralization but are, at present, difficult to fully explain.

Animals↗

PubMed2001

Determinants of cobalamin status in newborns.

OBJECTIVE: Cobalamin deficiency accompanied by bone marrow dysfunction and impaired central nervous system development has been reported in infants who were born to mothers with low cobalamin intake. We investigated the relation between cobalamin status in newborns and in their healthy mothers who consumed an omnivorous diet. METHODS: Serum cobalamin and the functional markers plasma methylmalonic acid (MMA) and total homocysteine (tHcy) were determined in 173 newborns and their mothers. Forty-five children and mothers were reinvestigated after 6 weeks. RESULTS: At birth, median (interquartile range) serum cobalamin levels were 245 (175-323) pmol/L in the mothers and 314 (238-468) pmol/L in the newborns. In the neonates, serum cobalamin, but not folate, was inversely associated with MMA and tHcy. Among maternal factors, low serum cobalamin was the strongest predictor of impaired cobalamin function (defined as low cobalamin, high tHcy, or high MMA levels) in the newborns. After 6 weeks, the maternal cobalamin levels had increased (to 421 [271-502] pmol/L), whereas the newborn levels had declined (to 230 [158-287] pmol/L). In the same interval, the infants had a marked increase in plasma MMA (from 0.29 [0.24-0.38] to 0.81 [0.37-1.68] micromol/L). At 6 weeks, parity was a strong predictor of cobalamin status in the infant. CONCLUSION: The cobalamin status in the neonatal period is strongly associated with maternal cobalamin status and parity. A reduction in serum cobalamin and an increase in metabolite levels are consistent with impaired cobalamin function in a significant portion of the infants who were born to healthy, nonvegetarian mothers.

Adult↗

PubMed2000

Biocompatibility and effect on osteogenesis of poly(ortho ester) compared to poly(DL-lactic acid).

Implantation of demineralized bone induces new bone formation by the action of contained growth factors, of which bone morphogenetic proteins are of prime importance. A biodegradable polymer may be used as a carrier for demineralized bone particles or recombinant bone growth factors to prevent displacement of the implant, preserve its volume and shape, and assure sustained release of the incorporated active components. A polymer for this use should be biocompatible and completely absorbed without interfering with the osteogenesis. We investigated the host-tissue response and effect on demineralized bone-induced bone formation by two biodegradable polymers, a poly(ortho ester) and an amorphous low-molecular poly(DL-lactic acid). Both polymers had a plastic consistency, could easily be molded, and adhered well to the demineralized bone particles. Demineralized bone particles were implanted alone and in combination with each of the polymers in the abdominal muscles of 45 male Wistar rats. Four weeks after the operation the implants were recovered and subjected to (85)Sr uptake analysis to quantify bone formation and histologic examination. The poly(ortho ester) provoked little inflammation; it was largely absorbed by 4 weeks, and no qualitative or quantitative effect on bone formation was found. The poly(DL-lactic acid) provoked a chronic inflammation with multinuclear giant cells, macrophages with engulfed material, and proliferating fibroblasts; part of the material was still present, and the bone formation was inhibited.

Animals↗

PubMed1999

[Mosaicplasty in articular cartilage injuries of the knee].

Articular cartilage has little ability to regenerate. Cartilage lesions usually persist, may provoke pain, swelling, locking and disability, and may predispose for development of osteoarthritis. Long-term results after traditional surgical techniques are unsatisfactory. In recent years, auto-transplantation of chondrocytes and osteochondral cylinder grafts aimed at reconstituting the chondral surface has been introduced. By the mosaicplasty technique, osteochondral grafts are transplanted from areas of little weight bearing at the outer limits of the trochlea to the focal lesion in the same knee. Since March 1998, 35 consecutive mosaicplasties in 33 patients (median age 35 years) have been performed at our hospital. The median area of the lesions was 2.8 sq. cm and the lesions were located at the femoral condyles, trochlea or patella. Six to twelve months post-operatively we found significant improvement of the Lysholm kneescore, from 40 (SD 14) pre-operatively to 84 (SD 14) (p < 0.001), and on the Cincinnati kneescore (pain, swelling, giving way, catching and as total evaluation). Short-term results are good regarding symptoms and knee function. The method is some-what complicated, especially when performed arthroscopically. There are few complications. Mosaicplasty may be considered in cartilage lesions of moderate size (1 to 5 sq. cm) on the femoral condyles, trochlea and patella.

Adolescent↗

PubMed1999

Organic leachables from polymer-based dental filling materials.

Results are reported from a study on the in vitro separation and identification of leachables from three different polymer-based dental filling materials by using a combined method of gas chromatography and mass spectrometry. The median number of separable organic leachables in these materials was between 14 and 22. Of these organic leachables the following were identified and quantified: DL-camphorquinone, 4-dimethylaminobenzoic acid ethyl ester (DMABEE), drometrizole, 1,7,7-trimethylbicyclo[2,2,1]heptane, 2,2-dimethoxy[1,2] diphenyletanone (DMBZ), ethyleneglycol dimethacrylate (EGDMA), and triethyleneglycol dimethacrylate (TEGDMA). Three of the leachables have previously been shown to provoke allergy. The range of log P(ow) values (representing the lipophilicity of these compounds) varied between 1.09 and 4.20. By multivariate data analysis, selected leachables from the tested materials were shown to separate into characteristic patterns. The results contribute to a characterization of potential hazardous compounds in polymer-based dental filling materials.

4-Aminobenzoic Acid↗

PubMed1998

[Treatment of focal cartilage injuries in the knee].

Chondrocytes in adult human cartilage have little mitotic capacity even after injuries. Deep injuries penetrating the subchondral bone plate lead to the release of pluripotent mesenchymal stem cells which have the potential to differentiate into different types of connective tissue, including bone and cartilage. The release and stimulation of these stem cells can also be achieved by drilling or microfracture of the subchondral bone of cartilage lesions. When stimulated, periosteal cells may also differentiate into chondrocytes. However, non-chondrocyte determined cells seem to induce mainly fibrocartilage. In 1987 autologous chondrocyte implantation was introduced by a team in Gothenburg. This resulted in clinical improvement and the development of hyaline-like cartilage in patients who had undergone treatment. We first used the method in 1996 in a clinical trial. At a 6-month follow-up of our first 12 patients we found reduced symptoms and improved knee function. This method is promising, but further clinical trials are necessary.

Adult↗

PubMed1998

Osteoinduction by demineralised bone.

Bone contains several growth factors, including bone morphogenetic proteins (BMPs), transforming growth factor beta (TGF-beta), insulin-like growth factors I and II (IGF-I and IGF-II), platelet derived growth factor (PDGF) and basic and acidic fibroblast growth factor (bFGF and aFGF). The BMPs are the only factors known to provoke bone formation heterotopically by making undifferentiated mesenchymal cells differentiate into osteoblasts (osteoinduction). Much of our knowledge of osteoinduction derives from studies in rodents of heterotopically implanted demineralised bone which contains various growth factors, including BMPs. This model has been used to examine the effect on osteoinduction of different factors, including the type of host soft tissue, age and species of donor and recipient, demineralisation procedure, storage and sterilisation procedures, experimental diabetes, dietary factors, hormones, growth factors, caffeine, biphosphonates, indomethacin and biomaterials. Demineralised bone enhances bone formation experimentally in various animal models, including cranio-maxillofacial reconstructions, healing of diaphyseal defects, and spinal fusion; demineralised bone has also been used in a limited way clinically. However, sufficient osteoinduction in humans may require a higher concentration of BMPs and other growth factors than those found in demineralised bone.

Animals↗

PubMed1998

Growth factors in bone.

Bone contains several growth factors, including bone morphogenetic proteins (BMPs), transforming growth factor beta (TGF-beta), insulin-like growth factors I and II (IGF-I and IGF-II), platelet derived growth factor (PDGF) and basic and acidic fibroblast growth factor (bFGF and aFGF). Spatial and temporal variations in the expression and secretion of the various growth factors have been demonstrated in osteoblastic cultures and in various experimental and clinical in vivo models, including fracture healing in humans. Local application of various growth factors influences proliferation, differentiation and protein synthesis in osteoblastic cultures and bone formation in different animal models, including experimental fractures and skeletal defects. The BMPs are the only growth factors known to provoke bone formation heterotopically by making undifferentiated mesenchymal cells differentiate into osteoblasts (osteoinduction). BMPs and other growth factors, soon to become commercially available for clinical use, need a delivery system for their sustained release, as the factors are otherwise rapidly absorbed. Some existing systems inhibit bone formation by inducing chronic inflammation or physically by unresorbed carrier obstructing bone formation. New delivery systems are being investigated.

Bone Development↗

PubMed1998

Osteoinductive potential of demineralized rat bone increases with increasing donor age from birth to adulthood.

Demineralized allogenic bone implanted in the subcutis or muscle of rodents causes formation of heterotopic bone by osteoinduction. The osteoinductive response may be weaker in primates than in rodents. It was suggested that the osteoinductive response of demineralized bone for clinical use could be enhanced by using young donors, because studies have indicated that the osteoinductive response is reduced in demineralized bone of old versus young donors. However, these findings may not represent a gradual decline in the osteoinductive property of bone matrix throughout the life span. We evaluated quantitatively, by uptake of strontium 85, the osteoinductive effect of demineralized bone matrix from newborn, 8-week-old (adolescent), and 8-month-old (adult) male Wistar rats implanted in the abdominal muscles of 8-week-old male Wistar rats. The osteoinductive response increased significantly with increasing donor age. The results of the present study, weighed with those of previous studies, indicate that the osteogenic potential of the bone matrix increases from newborn to adulthood but decreases in the aged rat. This may be due to changes in concentration of essential growth factors (e.g., bone morphogenetic proteins) resulting from maturational changes from birth to adulthood and osteoporotic changes occurring in later years. The results do not support the contention that young donors of demineralized bone are preferable to adult donors.

Abdominal Muscles↗

PubMed1997

Registration of cruciate ligament injuries in Norwegian top level team handball. A prospective study covering two seasons.

All cruciate ligament injuries in the three upper divisions for men and women (3392 players) in Norwegian team handball in the 1989-90 and 1990-91 seasons were registered. A questionnaire was mailed to all injured players. Ninety-three cruciate ligament injuries were registered; 87 in the anterior cruciate ligament (ACL), and six in the posterior cruciate ligament (PCL). Among women, 1.8% were injured compared with 1.0% of the men. In the first division, the risk of being injured was considerably higher: 4.5% of the players had a cruciate ligament injury. There were 0.97 cruciate ligament injuries per 100 playing hours in the three divisions taken together. Seventy-five per cent of the injuries occurred during games. Ninety-five per cent involved no contact between players. Activities in which the friction between shoe and floor was significant caused 55% of the injuries. Injuries caused by running into another player contributed to only 5% of the injuries. No significant differences were observed in injury incidence during matches between different types of floors (parquet, Pulastic and other synthetic surfaces.)

Adolescent↗

PubMed1997

Closed reduction and external fixation of unstable fractures of the distal radius.

The anatomical and functional outcome and complications after closed reduction and external fixation of unstable fractures of the distal radius were reviewed in 29 patients. The fractures were reduced by longitudinal traction and closed manipulation under fluoroscopic control, and the reduced position was retained by a standard half-frame Hoffmann external fixator for six to eight weeks. The mean follow-up time was four (3-7) years. The reduction failed in three patients after too early removal of the fixator (three to five weeks). For the rest of the patients the dorsal angulation, the radial length, the articular step-off, and the intra-articular gap between fragments were significantly improved. Twenty-two patients had excellent or good anatomical alignment and in seven it was fair. One patient had a superficial pin infection, six patients had transient paraesthesias, and one patient transient mild dystrophia. At follow-up one patient had some finger stiffness; this was the only persistent complication. The median Gartland and Werley functional score was 3. The functional end result was excellent or good in 22 patients, fair in four, and poor in three.

Adult↗

PubMed1997

Open reduction and internal fixation of displaced intraarticular fractures of the distal radius. 31 patients followed for 3-7 years.

We have used open reduction and internal fixation with a T-plate in 31 displaced, intraarticular fractures of the distal radius which were judged irreducible or in which closed reduction failed. The mean follow-up time was 4 (3-7) years. The dorsal angulation, the radial length, the articular step-off and the intraarticular gap between fragments were substantially improved after surgery. 30 patients had excellent or good extraarticular alignment, and only 1 patient had a postoperative intraarticular step-off of 2 mm. The function was excellent or good in 26 patients at follow-up. Complications occurred in 6 patients: 1 compartment syndrome, 1 postoperative wound infection, 2 ruptures of the extensor pollicis longus tendon, and 2 patients had median nerve paresthesias.

Adolescent↗

PubMed1997

Undiagnosed anterior cruciate ligament rupture. A common problem with poor prognosis.

BACKGROUND AND AIMS: Our knowledge on how often tears of the anterior cruciate ligament (ACL) initially remain undetected and the outcome of the resulting non-operative regimen is still incomplete. To investigate these issues, we conducted a follow-up study in young individuals that 4 to 5 years earlier had sustained a knee injury during a sports event that had been diagnosed as a first-degree sprain. MATERIAL AND METHODS: The patients (n = 54) were grouped according to present symptoms (pain or instability): A, no symptoms (n = 27), B, moderate symptoms (n = 16) and C, severe symptoms (n = 11). Eight group A patients, 11 group B patients and 8 group C patients participated in the follow-up study. Symptoms and level of activity were evaluated and clinical examination of the knee and KT-1000 instrumented measurement of anterior knee laxity were performed. RESULTS AND CONCLUSIONS: Increased anterior laxity was demonstrated in 7 patients (1 in group B and 6 in group C). In the same period these injuries occurred, acute ACL rupture was diagnosed in our region in 16 patients. The proportion of overlooked ACL ruptures to injuries interpreted as a first-degree sprain and to total number of ACL ruptures sustained during the same period was at least 7 out of 54 (13%) and at least 7 out of 23 (30%), respectively. The subjective symptom score was higher and Lysholm's and Tegner's scores lower in the patients with increased anterior laxity compared to the patients with no increased anterior laxity. We conclude that ACL rupture may be overlooked in a rather high proportion and that the 4-5 years' result in such injuries is poorer than in those without increased anterior laxity.

Adolescent↗

PubMed1996

Open tibial fractures treated with the Ex-fi-re external fixation system.

Fifty open tibial fractures were treated with the Ex-fi-re external fixation system from 1987 to 1994. According to the Gustilo and Anderson classification, there were 12 Grade I, 14 Grade II, 10 Grade IIIA, 13 Grade IIIB, and 1 Grade IIIC injuries. Eight fractures were segmental. The average patient patient age was 39 years (range, 16-85 years). With the reduction unit of the system, displaced tibial fractures could be reduced by the functions of the device in contrast to the manual reductions needed with other unilateral devices. Compression could be applied even to oblique fractures. The reductions were performed by this unit in all cases and were classified as exact in 28 of 41 cases. Exact reduction was defined as a reduction in which there was no more than 2 mm of translational displacement. The 8 segmental fractures were not classified according to reduction. Forty-three fractures healed with no secondary procedure. Three secondary bone graftings, 4 fibulotomies, and 3 renamed intramedullary fixations were performed in 6 patients. Thirty-two skin grafts were performed. There was 1 fracture site infection, and 1 curettage and 1 sequestrectomy were performed after union. At 1 year followup there were no signs of infection. Median time to union was 20 weeks, and median time to full unprotected weightbearing was 22 weeks. Fractures with an exact reduction had a median time of union of 19 weeks, compared with a median of 31 weeks in reductions with greater than 2 mm translational displacement. The exact reduction and translational compression applied in oblique fractures appeared to contribute to early consolidation.

Adolescent↗

PubMed1995

Local delivery of indomethacin by a polyorthoester inhibits reossification of experimental bone defects.

Inhibition of orthotopic reossification after surgical removal of bone is sometimes indicated and may be accomplished by implantation of interpositional materials or by systemic administration of indomethacin. However, implantation of nonresorbable foreign material may induce a chronic inflammation and predispose to infections; and systemic administration of indomethacin may induce systemic adverse effects. We studied the effect of local delivery of indomethacin by a bioerodible polyorthoester on the reossification of segmental defects of the radius in rats. We divided 45 Wistar rats into three groups, A-C. A 3.5 mm-long middiaphyseal osteoperiosteal resection of the right radius was made in each rat. The defect was filled with 15 mg of polyorthoester with 5% indomethacin in group A and 15 mg of polyorthoester without drug in group B. No material was implanted in the defects in the group C rats. The rats were killed 50 days postoperatively. The mean area of the residual defects were greater in the defects with the polyorthoester with 5% indomethacin compared with defects with polyorthoester without drug or without implant as judged by computer-assisted area measurements on radiographs. By light microscopy, no inflammation was seen and only traces of the polyorthoester could be detected in the defects filled with the polyorthoester with or without indomethacin. The results of this study suggest that the polyorthoester may be used as a bioerodible system for local delivery of indomethacin to inhibit reossification of skeletal defects without tissue reaction, unabsorbed carrier, or systemic effects.

Animals↗

PubMed1995

Clinical tests versus KT-1000 instrumented laxity test in acute anterior cruciate ligament tears.

Forty-two patients referred to the outpatient clinic of Hagavik Orthopaedic Hospital within 3 weeks after an acute knee injury was found by arthroscopy to have a partial or total tear of the anterior cruciate ligament (ACL). In these patients, the results of clinical tests and instrumented laxity tests without anesthesia prior to the arthroscopy were analyzed. The Lachman test and the maximum anterior pull (150-200 N) KT-1000 instrumented test revealed abnormal laxity in 33 and 37 of 42 cases, respectively. Both tests revealed abnormal laxity more often than the KT-1000 test using 67 N (10/42) and the maximum anterior pull KT-1000 instrumented test also revealed abnormal laxity more often than the KT-1000 test using 89 N (25/42). By logistic regression analysis, the maximum anterior pull KT-1000 instrumented test was associated with rupture of the ACL (partial or total rupture). The results show that adequate anterior pull has to be used to overcome muscle tension to reveal abnormal laxity in acute ACL tears using the KT-1000 arthrometer.

Adolescent↗

PubMed1995

Bone formation in cranial, mandibular, tibial and iliac bone grafts in rats.

Several studies have suggested that grafts from membranous derived bone (e.g., calvarial grafts) retain their volume better than those from endochondral derived bone (e.g., iliac bone grafts). Increased osteogenesis in grafts of the former type has been offered as the explanation. However, simple volume measurements of the recovered grafts do not differentiate between viable and dead bone. 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. Bone formation in grafts recovered 3 weeks postoperatively was quantitatively evaluated by strontium 85 uptake analyses. We found that the strontium 85 uptake was greater in calvarial and mandibular grafts than in tibial grafts. No difference was found among calvarial, mandibular, and iliac grafts or between tibial and iliac grafts. We conclude that the anatomical area of harvest is important regarding new bone formation in syngeneic bone grafts. However, the results do not support the contention that better maintenance of volume of calvarial grafts compared with iliac bone grafts is due to enhanced osteogenesis in the former.

Animals↗