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Biomedical subjects

P Lereim

Publications and source records attributed to P Lereim.

At least 19 recordsLinked to original sources
PubMed1991

Bone grafts in T-cell deficient rats.

Revascularization, new bone formation, and resorption of fresh syngeneic and allogeneic cancellous bone that were transplanted to an intramuscular pouch have been studied in athymic and normal rats. Revascularization was evaluated with radioactive microspheres; formation of new bone was assessed with 85Sr incorporation; and resorption was measured by the graft weight reduction. Animals were killed 2, 6, or 12 weeks after transplantation. The circulation and bone formation in allogeneic grafts were greatly impaired in normal rats as compared with the athymic group and the syngeneic grafts. The allografts in normal rats had a smaller weight reduction than the allografts in athymic rats, suggesting impaired resorption. We conclude that the T-lymphocyte system is at least partly responsible for the difference between syngeneic and allogeneic bone grafts, and that the thymus-dependent primary rejection mechanism probably is important for the vitality of allogeneic bone grafts.

Animals↗
PubMed1988

Piroxicam and naproxen in acute sports injuries.

The efficacy of piroxicam versus placebo was studied in a double-blind, randomized trial of 74 patients with traumatic injury of muscle, periosteum, bursa, or ankle joint. The piroxicam dosage was 40 mg once daily for two days and then 20 mg daily for an additional five days. Efficacy parameters were assessed at entry and at three, seven, and 14 days. At the Day 3 visit, there was a statistically significant improvement in the piroxicam group for pain at rest, pain on movement, pain on palpation, reduced muscle force, and general limitation of function. At the Day 7 visit, the difference was still significant for pain on palpation and reduced muscle force. Mean time required for full relief of symptoms was 7.5 days in the piroxicam group and 10.2 days in the placebo group. The anti-inflammatory effects of piroxicam and naproxen were then compared in 254 patients experiencing the same types of injuries mentioned above. The dosage of piroxicam was the same as in the comparison with placebo, whereas naproxen was given 500 mg twice daily; treatment in both groups lasted for five days. There was no difference in most parameters for pain, swelling, and function. There was a significant difference in favor of piroxicam for tenderness on palpation and time to complete relief of symptoms.

Acute Disease↗
PubMed1985

Trigger toe in classical-ballet dancers.

Classical ballet involves extreme physical demands on the body--in part, strains beyond the physiological limits. Balance on the tips of the toes en pointe means extreme plantar flexion of the ankle and first toe in the weight-bearing position. We have treated two cases of stenosing tendovaginitis of the flexor hallucis longus tendon. A 22-year-old male dancer had been suffering from pain on the postero-medial aspect of the ankle at weight bearing for 6 months, when bilateral locking of the great toe going from en pointe to the neutral position occurred. At operation a fusiform thickening of the tendon of the flexor hallucis longus was found. After partial excision of the tendon sheet and partial incision of the retinaculum the tendon moved freely in its groove. Six months postoperatively the patient was free of symptoms. The second case was a 17-year-old female professional dancer with unilateral trigger toe. A similar surgical procedure was performed and the symptoms disappeared. Once the condition is known, the diagnosis is easy. Surgical excision of stenosing structures is the treatment of choice.

Adolescent↗
PubMed1983

Total surface hip arthroplasty in dogs using a fiber metal composite as a fixation method.

A total hip surface replacement was performed on 13 adult mongrel dogs using a porous fiber metal composite for fixation to bone. Titanium fiber composite rings were molded onto cylindrical acetabular prostheses, and cobalt-chrome fiber inserts were sintered onto the cast cobalt-chrome femoral components. The animals were allowed unrestricted walking. Four dogs were sacrificed between 3 and 5 weeks, five at 7 weeks, one with a femoral neck fracture at 12 weeks, and three at 26 weeks. Bone ingrowth was accomplished in 20 of the 26 prosthetic components. This included 12 femoral components and eight acetabular. The main reason for failure appeared to be inadequate primary fixation, secondary to either poor design or technical difficulties experienced during the surgical procedure.

Animals↗
PubMed1982

Segmental replacement of the femur in baboons with fiber metal implants and autologous bone grafts of different particle size.

A study was made of bone ingrowth into fiber metal composite prostheses used to replace large segments of the femur in baboons. Bone grafts of two different types were used to cover the segment: chips of bone with large particle size and ground bone with a smaller particle size. The prosthetic segment was bridged by bone at 3 and 6 months in all cases irrespective of the structure of the transplant. In animals sacrificed at 6 months bone ingrowth occurred, with a marked difference between specimens with the two different grafts. In the ground bone specimens ingrowth occurred over the total surface area, and bone penetrated deep into the composite. With the chip grafts ingrowth was more irregular occurring only in some areas and it was always superficial. The difference is believed to be due to the improved contact between the fiber metal surface and the transplant. The lesser bulk of the ground transplant is advantageous when the soft tissue cover of the bone is thin.

Alloys↗
PubMed1979

Effect of an in vivo environment on the strength of bone cement.

Bar-shaped polymethylmethacrylate test specimens removed from rabbits after implantation for times up to 26 months showed a significant change in fracture stress as determined by three-point bending in the period between 12 and 26 months. There were no adverse findings in the tissue which developed around the bone-cement test bars.

Animals↗
PubMed1978

Evaluation of couple/crevice corrosion by prosthetic alloys under in vivo conditions.

Alloys of cast Co-Cr-Mo, wrought Co-Cr-W, wrought, Co-Ni-Cr-Mo(MP35N), Ti-60% Al-4% V, and graphite were incorporated in specimens which simulated both a couple and a crevice corrosion condition. These specimens were implanted in a dog for 30 months. Post-sacrifice examination showed no substantial evidence of corrosion activity on the surfaces of the metals except for a tarnish film on the titanium alloy specimens. The presence of the tarnish film is taken as more evidence of corrosion activity and this correlated with a thicker average fibrous membrane, cellular activity in and near the fibrous membrane, and some increased vascularity. These must be regarded as preliminary observations.

Alloys↗
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

Relationship between morphologic features and hardness of the subchondral bone of the medial tibial condyle in the normal state and in osteoarthritis and rheumatoid arthritis.

In osteoarthritis and rheumatoid arthritis the hardness of the subchondral bone of the medial tibial plateau is lower than in normals. In order to further analyse this study of the morphologic characteristics in bone from the mentioned region was carried out in 22 normals, 14 osteoarthritis and 12 rheumatoid arthritis. Specimens from these groups were subjected to a radiologic assay, a light microscopic investigation and an evaluation of the occurrence of intraosseous lipids. The normals showed a remarkable integrity of the subchondral trabecular network with advancing age only with slight osteoporosis and occasional sclerosis. In osteoarthritis there were osteoporosis, osteolysis, sclerosis and osteophytes all in good correlation to the grade of osteoarthritis present. In rheumatoid arthritis there were areas of rarefaction, fractures of the trabeculae, sclerosis and invasion of granulation tissue. The radiologic appearance corresponded well with the morphologic observation. No abnormal presence of lipids was encountered. This investigation supports the concept that the hardness of the subchondral bone of the medial tibial plateau much depends on the morphologic structure of the bone.

Adult↗
PubMed1975

Physical work performed by surgeons during orthopaedic operations.

Four surgeons participated in a study which aimed to demonstrate the physical work load during operations. Maximal oxygen uptake and maximum heart rate were determined by using the Douglas bag technique and recording the heart rate during the tests. By working at two submaximal work loads, heart rate was recorded and miximal oxygen uptake was determined indirectly. Using telemetry, heart rate was recorded during operation, and the mean oxygen uptake was determined. In 90 per cent of all operations the surgeons were working at a level of 20 to 30 per cent of their maximal aerobic capacity. There was an increase in body temperature and a decrease of body weight after all operations. In long lasting operations a decrease of grip force was noted.

Adult↗
PubMed1975

A biochemical analysis of subchondral bone of the medial tibial condyle in the normal state and in osteoarthritis and rheumatoid arthritis.

A chemical analysis has been carried out on specimens from the subchondral weightbearing area of the medial tibial condyle from 22 normal individuals, 14 individuals with osteoarthritis and 12 individuals with rheumatoid arthritis. In the normal group there was a decrease in density with advancing age. Over the age of 50 there was no significant difference between the groups. The content of collagen, calcium, phosphorus and magnesium in each bone specimen was calculated. When expressed in per cent of dry fat free bone there was no significant difference between the three groups. When calculations were made on the basis of content per volume tissue wet bone some differences were found. There was a tendency for a higher content of collagen in rheumatoid bone than in normal and osteoarthritic bone. The content of calcium was significantly higher in rheumatoid arthritis than in osteoarthritis; the same result was found in the analysis of phosphorus. In the normal group there was a decrease in phosphorus content with advancing age, this was also seen in the magnesium analysis.

Adult↗