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Biomedical subjects

M Liebergall

Publications and source records attributed to M Liebergall.

At least 37 records · Page 2Linked to original sources
PubMed1998

Effect of moderate bone hyperthermia on cell viability and mechanical function.

Extracorporeal hyperthermia treatment of bone followed by its reimplantation may be an optional treatment of bone tumors. In this study, the authors examined the minimal hyperthermic condition in which complete eradication of all viable cells in rat bone can be achieved and the mechanical effect of this treatment on the tested bone. When the results were evaluated histologically by special lactate dehydrogenase activity staining, it was found that complete bone cell death occurred after 30 minutes of heating at 60 degrees C. Cartilage cells, including those of the epiphysis, were more resistant to thermal damage. When the ability of the specimens to proliferate in cell cultures was tested, no growth was observed after heating at temperatures of 50 degrees C or greater. The mechanical stiffness tested in the Instron machine showed decreased bone stiffness at 70 degrees C but no change in the breaking load of the bones. Controlled hyperthermia's ability to eradicate viable cells without significant damage to the mechanical properties may have clinical relevance in limb salvage tumor surgery.

Animals↗
PubMed1998

A comparison of the effect of shoes on human tibial axial strains recorded during dynamic loading.

Percutaneous axial extensometers were mounted on the medial cortex of the midtibial diaphysis in seven male volunteers and the effect of three different shoes on in vivo peak-to-peak axial compression-tension strains measured during dynamic loading. Zohar shoes had lower axial strains and strain rates during treadmill walking than Nike Air Max running shoes or Israeli infantry boots. During running on a running track, there was no statistically significant difference between the axial strains or strain rates between the shoes tested. Shoe gear can modify tibial strains and strain rates that contribute to the development of tibial stress fractures.

Adult↗
PubMed1998

Midshaft femoral fracture, concomitant ipsilateral hip joint injury, and disruption of the knee extensor mechanism: a unique triad of dashboard injury.

Our experience with 10 patients who suffered midshaft fractures of the femur and injuries to their ipsilateral hips has resulted in a treatment protocol that we believe can avoid unnecessary complications. The surgical protocol is a three-stage procedure based on (1) intramedullary nailing of the femur with interlocking for preserving the anatomic length and rotation of the femur; (2) treatment of the hip joint injury by means of open reduction and internal fixation of the acetabular fracture and/or reduction and fixation of the fractured femoral neck; and (3) repair of the extensor mechanism. Eight patients received this treatment and had fast recoveries. Union of the femoral fracture and full range of motion of the knee joint were observed within 3 months. In contrast, two patients who had received different surgical treatment had incomplete functional recoveries. This study offers a treatment protocol for ipsilateral disruption of the extensor mechanism, hip joint injury, and midshaft fracture of the femur in the multiply injured patient that can achieve full recovery with no complications. This relatively rare combination of injuries is definitely worthy of special attention.

Accidents, Traffic↗
PubMed1997

[Immediate orthopedic surgery in multiple trauma].

The increase in mortality and morbidity from multiple trauma due to road accidents, industrial trauma and combat injuries obligates treatment based on emergency systems and trauma centers. Follow-up of the frequency of different types of injury calls attention to increasing involvement of the orthopedic surgeon in primary treatment. This situation calls for appropriate deployment of immediate surgical treatment which will rapidly enable mobility. We present several methods for immediate orthopedic treatment of multiple-trauma patients.

Bone and Bones↗
PubMed1997

[Treatment of open fractures due to dog bite].

2 patients aged 12 and 19, respectively, sustained open fractures of the wrists due to dog bites. Both were bitten on a wrist by Rotweiller dogs, but with different magnitudes of injury to bone and soft tissue. Treatment, clinical course and recovery are described, together with recommendations for dealing with open fractures due to animal bites. In the presence of considerable injury to soft tissue and bone, and of exposure to canine oral flora, open fractures due to dog bites should be dealt with as high grade open fractures.

Adolescent↗
PubMed1997

Nonunion of a fracture of the lateral malleolus: a case report and review of the literature.

Nonunion of a fracture of the lateral malleolus is a rare condition. We present a case of established nonunion of a fracture of the lateral malleolus confirmed and treated surgically, using debridement and internal fixation with autologous bone graft. At 5-year follow-up, the fracture was united but the patient still showed clinical signs of reflex sympathetic dystrophy. Male gender, supination fractures, Weber type C fractures, and primary internal fixation are cited as possible risk factors. Prognosis is variable.

Adult↗
PubMed1997

Cyclosporin A and its non-immunosuppressive derivative exhibit a differential effect on cell-mediated mineralization in culture.

Chronic immunosuppressive treatment with cyclosporin A (CsA) is associated with decreased bone density. However, in culture, CsA inhibits osteoclast differentiation and bone resorption. This raises the question as to whether CsA also affects osteoblast function. Immunophilin, one of the CsA-binding cyclophilins that is implicated in the immunosuppressive action of CsA via calcineurin, is a peptidyl prolyl cis-trans isomerase (PPl). CsA also binds a mitochondrial membrane PPl which is implicated in controlling permeability transition pores. Therefore, in the present study we tested the effect of CsA on cell mediated mineralization in parallel with mitochondrial rhodamine retention as an indicator of mitochondrial membrane potential Rat marrow stromal cells were grown in dexamethasone (DEX) medium to stimulate mineralization in culture, and CsA was added to various cultures using different treatment schedules. Low dose (0.1 microM) CsA inhibited mineralization, compared to controls, when present in the cultures during days 3-11 of DEX stimulation. Contrarily, high dose CsA (1.0 microM) resisted the inhibitory effect of the low dose. SDZ 220-384 (SDZ), a non-immunosuppressive derivative of CsA which is known, like CsA, to bind to mitochondrial cyclophilin but does not inhibit calcineurin, was also tested. Both high and low doses of SDZ decreased mineralization when present in the cultures from day 3 or from day 0. The similar effect of the low CsA dose and SDZ on mineralization is in accord with their ability to block permeability transition pores. The differential effect, on day 21 mineralization, between high CsA dose and SDZ took place in parallel to their opposing effects on mitochondrial membrane potential. On days 4-8, mitochondrial rhodamine retention was higher under CsA than under SDZ. Under these conditions there was no significant difference between the effects of these drugs on cell proliferation measured on day 11; there was a minor decrease in specific alkaline phosphatase activity by SDZ, too small to explain the extent of mineralization inhibition by SDZ. These results suggest that permeability transition pores might be involved in controlling mineralization. Unlike SDZ, CsA exhibits an additional effect on the mitochondrial membrane potential and on mineralization when applied at a high dose on day 3. Therefore identifying the additional activity of high dose CsA, which is missing in SDZ, may be beneficial. Such activity is expected to resist changes in rhodamine retention and decreased mineralization induced by SDZ, and yet enable preservation of immunosuppressive activity of CsA.

Alkaline Phosphatase↗
PubMed1997

[Surgical repair of fractures of the clavicle in the adult].

Clavicular fractures make up 45% of shoulder girdle fractures. The clavicle's susceptibility to injury is due to its subcutaneous position and its role as the bony connection between the thorax and the shoulder. In 95% of cases the mechanism of injury is a direct blow to the shoulder. These fractures are usually treated conservatively without surgery. But there are a few such fractures that require surgical repair in order to unite well. 9 patients were operated on for clavicular fractures during 1991-1995. The indications for surgical repair were lateral-third fracture, floating shoulder, neurovascular deficit or nonunion. The methods used were open reduction and fixation with either plate and screws, Kirchner wires, cerclage or a combination. All fractures united well, with no infections or new neurovascular deficits. Good range of shoulder motion and acceptable cosmetic results were achieved in all. 1 patient had functional limitation due to brachial neuritis caused by brachial damage at the time of injury. Indications for surgical repair and the methods used in these cases are similar to those described in the literature. The high rate of union and absence of complications support surgical repair for the few calvicular fractures that are not likely to unite properly.

Adult↗
PubMed1997

Alveolar macrophages fat stain in early diagnosis of fat embolism syndrome.

The aim of this study was to assess the contribution of bronchoalveolar lavage (BAL) in the diagnosis of fat embolism syndrome (FES). The presence of fat droplets in alveolar macrophages was addressed in 13 trauma patients with bone fractures and 10 non-trauma patients with acute respiratory distress syndrome (ARDS). The control group was composed of 5 anesthesized patients with ischemic heart disease, immediately prior to cardiac surgery. Two patients with suggestive clinical and laboratory signs of FES had 40% and 24% fat-containing alveolar cells, respectively. The trauma patients without signs of FES displayed a wide variation in the percentage of fat-containing macrophages (from 3% to 95%). Most of the patients with ARDS who were receiving lipid emulsion as part of their parenteral nutrition, had a high percentage (> 85%) of fat-containing macrophages. Patients with normal lungs had no fat-containing macrophages. Our findings suggest that BAL Oil Red O-positive macrophages are frequently observed in trauma patients irrespective of the presence of FES. Therefore, estimation of the percentage of fat-containing macrophages from BAL is an unreliable marker of FES.

Adult↗
PubMed1996

The effect of shoe gear on human tibial strains recorded during dynamic loading: a pilot study.

The study was conducted to test the hypothesis that alterations in shoe gear can affect tibial strains in the human during dynamic loading. Rosette strain gauges were mounted on the medial border of the mid-diaphysis in two human subjects with a new strain gauge bonding technique using methyl methacrylate. Strain measurements were made at this site, the most frequent location for stress fractures in the Israeli Army during treadmill walking and free running while wearing various sport shoes (Rockport ProWalkers and New Balance NBX 900) and army boots (light Israeli infantry, double layered sole Israeli infantry, and Zohar infantry boots). Data were analyzed for only one of the subjects because strain gauge bonding was found to be inadequate at the time of surgical removal in the other subject. No single shoe lowered both the principal tibial compression and tensile strains, and the shear strains. The Zohar boot had the lowest principal compression strains during treadmill walking and mobile running, despite its relatively higher weight and sole durometry.

Biomechanical Phenomena↗
PubMed1995

Analysis of cell-mediated mineralization in culture of bone-derived embryonic cells with neurofibromatosis.

von Recklinghausen neurofibromatosis (NF1) is an autosomal dominant genetic disorder associated with congenital pseudoarthrosis and with short stature. To examine whether the NF1 phenotype includes functional osteogenic defects, embryonic bone-derived cells affected with NF1 were tested in culture for specific alkaline phosphatase (ALP) activity and cell-mediated mineralization and compared with other embryonic bone derived cells. NF1 showed a relatively higher specific ALP activity, which has further increased in response to dexamethasone + beta-glycerophosphate (beta GP) (Dex medium) coordinately with a decrease in cell proliferation. In In the control group, two samples showed increased ALP activity, one showed decreased activity and the forth one did not show any change in ALP. NF1 cells were distinguished from other cells regarding day 21 mineralization, they did not mineralize when cultured with ascorbate alone in the absence of Dex medium, whereas control cells did mineralize. Adding beta GP resulted in mineralization by NF1 cells but less than in other cells. In addition, NF1 cells responded to dexamethasone by increasing the beta GP-induced mineralization, as opposed to cells from other embryonic bones, which either did not respond or have even decreased mineralization under dexamethasone. Upon cis-hydroxyproline exposure, Dex medium has also distinguished NF1 cell ALP activity from that of other cell origins. Inhibition of respiratory complex II by malonate showed that most embryonic bone-derived cells of 12 weeks gestation are malonate resistant; thus, malonate selection was ineffective. This is in contrast to rat marrow stromal cells previously shown to undergo mineralizing cell enrichment in response to malonate. Exposure to levamisole, of Dex-treated cells, at days 0-11 has inhibited day 21 mineralization in all tested cultures in spite of the increase in day 11-specific ALP activity. Both malonate and levamisole did not distinguish NF1 cells from the osteogenic phenotype of other cells. Essentially embryonic bone-derived cells from 12 weeks gestation, cultured in the absence of beta GP, retained their mineralization capacity, which does not increase under dexamethasone, as distinguished from NF1 cells which require beta GP for mineralization and positively respond to dexamethasone. Therefore, bone-derived NF1 cells may be useful for studying the regulation of the mineralization process.

Alkaline Phosphatase↗
PubMed1995

Tibial implant mineralization in rats is inversely related to serum osteogenic capacity.

In this study, the correlation between the mineralization of healing bone defects and the osteogenic capacity of the serum was tested in rats. The purpose of the study was to test the hypothesis that during callus formation, some serum factors are consumed. The bone defects in the tibia contained two different implant types, and all sustained juxta-implant fractures. One implant type was the coral Porites and the other was its recrystallized version (Interpore-200), which exhibit different mineralization rates during fracture healing. Use of these two implant types permitted generation of an expanded mineralization spectrum suitable for regression analysis. Mineralization was assessed by measuring the mineral content change (MCC) using dual-energy X-ray absorptiometry. Osteogenic capacity of sera of the implanted rats was assessed by its ability to increase specific alkaline phosphatase (ALP) activity in stromal cell cultures. The MCC was followed for 5 weeks in the Porites and Interpore-200 implants, and it was found that the MCC in Interpore-200 implants exceeded that of the Porites implants. Thus, the two implant types generated a wide mineralization spectrum. Induction of ALP in stromal cell culture was lower for sera derived from rats implanted with Interpore-200 than for sera derived from rats implanted with Porites. Two weeks after implantation, the change in serum ALP induction correlated inversely with the MCC of bone defects. This indicates that during callus formation, the mineralization rate is reciprocally related to the serum osteogenic capacity. The decreased serum osteogenic capacity may be interpreted by the hypothesis that callus formation consumes certain serum osteogenic factors.

Alkaline Phosphatase↗
PubMed1995

A double-blinded, randomized, controlled clinical trial to compare cefazolin and cefonicid for antimicrobial prophylaxis in clean orthopedic surgery.

A double-blind, prospective randomized study was performed to compare cefazolin and cefonicid given for prophylaxis to 102 patients undergoing orthopedic surgery. Risk factors (e.g., age, sex, type of operation performed) among the two groups were similar. All patients had foreign material (prosthesis or other hardware) inserted at operation. There was a total of 6 infections (3 wound and 3 urinary tract) in 6 patients among the 48 receiving cefazolin (12.5%), whereas no infections were observed among the 54 patients who received cefonicid. Cefonicid, given once daily, provides protection against postoperative infection that is not inferior to cefazolin. A larger study is needed to confirm whether cefonicid is indeed superior to cefazolin.

Adolescent↗
PubMed1994

The role of intramedullary nailing in modern treatment of open fractures of the tibia and femur.

The increasing incidence of open tibial and femoral fractures causes great suffering by patients and is an enormous economic burden, necessitating improved treatment. The current treatment of these fractures is reviewed, as well as the evolving role of intramedullary nailing in this treatment. Intramedullary nailing seems to give better results than external fixation in Gustilo type I and II fractures, and is at least as good in type III. The introduction of the non-reamed interlocking intramedullary nail may bring about even better outcomes. Any improvements in treatment should be based on thorough understanding of the biology and biomechanics of the injury.

Bone Nails↗
PubMed1994

Acute postpartum inflammatory sacroiliitis. A report of four cases.

We report four patients with unilateral postpartum sacroiliitis presenting with agonising unilateral pain, an elevated ESR, elevated alkaline phosphatase levels, leucocytosis and positive bone scans. The diagnosis of a non-infectious inflammatory cause was supported by the postpartum onset, the response to non-steroidal anti-inflammatory drugs, negative aspiration cultures in two cases and the lack of changes in the sacroiliac joints on long-term follow-up radiographs.

Acute Disease↗