Pig Femur Research Articles

Ultrasonic Measurement of Thicknesses of Bone and Bone Marrow within Femur Inserted with a Metal Stem.

The thicknesses of bone and bone marrow within a pig femur inserted with a metal stem of the total hip replacement system are investigated non-destructively by means of an ultrasonic technique. First, the wave velocities of bone and bone marrow are determined using the pulse echo method and thereby observing the time intervals between the first and the second echoes in these specimens. Next, an ultrasonic wave is emitted toward the femur inserted with the metal stem which is immersed in a water tank, and the distances from a normal probe to the boundary surfaces of bone and metal stem are measured. Subsequently, the actual thicknesses of the bone and the bone marrow are measured using vernier calipers. These measured results using the ultrasonic wave and the vernier calipers are compared and are graphically presented. Thus, the ultrasonic method is practically useful for the measurement of the bone and the bone marrow within the femur inserted with the metal stem.

A method for bone-cement interface thermometry: An in vitro comparison between low temperature curing cement Palavit® and Surgical Simplex® P

Previous temperature measurements at the bone-cement intreface have all shown large variations. To evaluate more precisely the temperature profiles during cement curing, a new experimental model was developed. Eight thermocouple electrodes at the bone-cement interface for each test specimen were used for continuous temperature recordings. Temperature profiles of Palavit was compared with those of Surgical Simplex P in an in vitro model using isolated pig femurs. Defects of 12 x 17 mm in the femoral metaphysis were filled with cement. In six tests with each type of cement, Palavit peaked at a temperature of 50 +/- 0.5 degrees C, whereas Surgical Simplex P peaked at 60 +/- 0.7 degrees C. Core temperatures reached peak values of 70 +/- 0.8 degrees C and 95 +/- 2.2 degrees C for Palavit and Surgical Simplex P, respectively.

Femoral shaft perforation at arthroplasty: To treat or not to treat

Femoral shaft perforation at total hip arthroplasty is a complication that is being noted more frequently, and it is often associated with femoral shaft fracture below the prosthesis. This study examines the anatomic and biomechanical effects of femoral shaft perforation at arthroplasty, and the effects of supporting the perforated bone with Partridge plates and bands. Two models, pig femora and Pedilen cylinders, were employed. Testing the bone models to failure in tensile mode showed that the perforations weakened the bone and that the Partridge plates and bands decreased the weakening effects of the perforation. The strengthening effect of the Partridge plates and bands on the bone with a perforation, allied with the presence of an internal splint in the event of a fracture through the perforation, suggests the benefit of using Partridge plates and bands if a cortical perforation is found at arthroplasty and revision is not feasible.

The mechanical effects of femoral shaft perforation at total hip replacement.

Perforation of the femoral shaft at total hip arthroplasty is a complication which is being reported more frequently. It has been suggested that the presence of bone cement in the perforation decreases the weakening effect of the perforation, but the mechanical basis for this belief is dubious. The anatomy of perforation was studied by cadaver dissection and its mechanical consequences were assessed in two models using Pedilen, a polyurethane foam, and pig femora. It was found that cement in a hole in bone decreased the weakening effect of the hole to tensile stress.

Coefficient of static friction at pig femoral osteotomies: the role of anatomic reduction and compression on the value of the coefficient

The coefficient of static friction for pig femora following an osteotomy has been determined in vitro. It was found that the coefficient had a value of 0.46 ± 0.05, and that this was independent of the reduction force applied to the osteotomy site, provided there was good anatomical reduction. When the osteotomy was not anatomically reduced, the coefficient of friction varied in a linear manner with the applied reduction force.

A model of experimental post-traumatic osteomyelitis in guinea pigs.

A model of experimental post-traumatic osteomyelitis is described in which the femur of guinea pigs was fractured and infected with E. coli (10(5)) or Staphylococcus aureus (10(4)). Traumatized uninfected animals served as controls. The animals were further divided within each group by treating the fractured site with an intramedullary wire in one half. Osteomyelitis developed and became chronic in all guinea pigs infected with Staph. aureus, and in nine of 12 infected with E. coli. All animals infected with E. coli treated with an intramedullary wire developed chronic osteomyelitis; only four of seven from E. coli-infected animals with fractures developed this disease. Moreover, Staph. aureus could be recovered from the osseous tissue in the chronic stage of the disease regularly, while E. coli was only present in the early weeks after operation, but not in the chronic stage.

Immunologic response to melanoma of sensitized perfused bone and spleen.

AbstractA B16 mouse melanoma which will not grow in tissue culture was implanted subcapsularly in 12 isolated perfused pig spleens and subperiosteally in four perfused pig femurs. Tumor implants grew to a maximum 3‐mm size within five to seven days. Metastases developed within the substance of the spleen but not within bones during the 7 to 15 day perfusions. The protective effects of perfustate, concentrated perfusate cells, and suspensions of spleen cells were determined by injecting the fluid fractions simultaneously with melanoma in 25 mice. Concentrated perfusate cells and splenic cells from perfusions over 10 days characteristically prolonged the mean time of tumor appearance and mean survival time of mice inoculated with melanoma. The possible immunologic mechanisms responsible for such protection are discussed.

Leukocyte-Mobilizing Factor: A New Biologic Activity Derived from the Third Component of Complement

Abstract To recognize leukocyte-mobilizing activity, a simple test system was developed. It consisted of a rat or guinea pig femur perfused at a steady rate with medium 199. Leukocyte-mobilizing factor (LMF) was recognized by an increase in the number of cells in the effluent following addition of the test substance to the perfusate. LMF was found in the supernatants of the reactions of sensitized erythrocytes or other antigen-antibody complexes and the sera of either (1) rabbit, (2) guinea pig, (3) mouse, (4) rat or (5) the human. Similar results were obtained when C6-defective rabbit serum (Cdef) or C5-defective mouse serum was used instead of the reactants 1–5. LMF was also observed when purified rabbit β1C-globulin was incubated with functionally pure C1, C4 and C2, but not if any one of the four reactants was absent from the mixture. At pH 6.5 and 20°C, LMF was not precipitated from activated serum in 3.2 M ammonium sulfate.

The microcirculation of the bone marrow.

AbstractThe microcirculation in the bone marrow has been studied in the femur, tibia, and humerus of guinea pigs, rats, and rabbits. Used were whole mounts of bone with bone marrow in situ, perfused and not perfused with India ink, thick sections (0.5 to 1.0 mm) of the same material, and also serially cut histological sections. It is concluded that the major blood supply to the bone marrow is transosteal. Direct intramyeloid connections of the arborizations of the nutrient artery with the sinusoids are rare. The great majority of the terminal capillaries of the nutrient artery enter the bone, where they anastomose with the intraosteal vessels which in turn connect with the sinusoidal network at the osteomyeloid junction. In addition, numerous direct links exist between the periosteal vessels and the vessels in the osteal canals.

An electron microscopic study on the reticuloendothelial system in the bone marrow.

The reticulo-endothelial system and fat cells of red bone marrow of the femur of guinea pigs, rats and rabbits was examined with the electron microscope. 1. The reticulo-endothelial tissue in the bone marrow consisted of reticulum cells and sinal endothelium. 2. The reticulum cells were characterized by large pale cytoplasm and a number of slender cytoplasmic processes which were thought to be connected with those of adjacent reticulum cells to form a cellular network. They also projected thin sheet-like processes toward the sinal walls and fat cells to cover their outer surface. 3. The sinal wall consisted of a single layer of endothelial cells. Only rudiments of basement membrane were present surrounding the sinal wall. The sinal endothelium showed gaps of various sizes, which were thought to be formed by the fenestration of the cytoplasm. Pseudopod-like processes of reticulum cells were seen to project into the sinal lumens through the endothelial gaps. 4. The fat cells contained single large fat droplets occupying the most part of the cytoplasm. In the perinuclear portion of the cytoplasm, a number of small droplets and glycogen granules were present. Basement membranes were seen surrounding fat cells. 5. After irradiation of 60Co, a marked proliferation of reticulum cells and fat cells were observed. The proliferated reticulum cells showed more abundant cytoplasmic organelles than normal ones and possessed numerous irregular cytoplasmic processes. On their surface were formed fibrous materials probably corresponding to reticulin fibers, which were not observed in normal cases. 6. As compared with endothelial cells of normal sinuses, those of irradiated cases showed thicker cytoplasm, prominent tight junctions and more complete basement membranes. Endothelial gaps were not observed in later stages of irradiation.

Effect of cortisone, thyroxine and cold on femurs of guinea pigs

The femurs of guinea pigs were analyzed for total mineral, collagen and hexosamine contents following daily administration of 25 µg of l-thyroxine and/or 60 mg/kg of cortisone acetate for 30 days. As judged from values predicted from femur length, cortisone markedly inhibited growth; mineral and hexosamine contents were consistent with growth, and collagen content was greater than predicted. Thyroxine did not reduce growth of femurs but caused less of its constituents to be deposited. Animals exposed to 2°–4°C for 90 days demonstrated a growth pattern and femur composition similar to that observed in thyroxine-treated animals. When cold-exposed animals were returned to room temperature and permitted to attain the weight of the unexposed controls, even though femur length was as great or greater, mineral, collagen and hexosamine contents were below the predicted values.

Phagocytic Activity of Bone-Marrow Cells

In view of the fact that there is a vigorous opsonic response to the parenteral injection of antigenic fractions of Brucella cells, an unusual opportunity is offered for measuring the phagocytic activity of the various types of bone marrow cells collected directly from the marrow, or as they are found in the peripheral blood in myelogenous leukemia. Studies have been made on the phagocytic activity of marrow cells aspirated from the cavity of the femur of normal guinea pigs, and those immunized to Brucella, and on marrow cells in the peripheral blood of one human case of chronic myelogenous leukemia. The cells in the blood of the pigs were measured for their Brucella phagocytic activity in vitro prior to the collection and examination of marrow cells. The cells in the whole blood of normal pigs showed no phagocytic activity. The segmented and stab neutrophile forms in the whole blood of the immunized pigs were found to ingest at least SO or more bacteria; thus indicating the presence of immune opsonins in the serum for Brucella. The phagocytic activity of marrow cells from normal and immunized guinea pigs was measured in vitro in the presence of both normal guinea pig serum and serum containing immune opsonins. The phagocytic activity: of the marrow cells in the peripheral blood of the case of myelogenous leukemia was examined in the presence of the patient's serum and in the presence of a serum obtained from another person possessing a high immune opsonin titer for Brucella. The mixtures of cells, serum and bacteria, were incubated in a water-bath at 37°C. for 30 minutes before making spreads and staining.