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Biomedical subjects

A E Goodship

Publications and source records attributed to A E Goodship.

105 records · Page 6Linked to original sources
PubMed1979

Functional adaptation of bone to increased stress. An experimental study.

In young pigs walking normally, we recorded the principal compressive strains (epsilon 2) as revealed by strain gauges attached to the shaft of the radius. We found no correlation between the mean principal compressive strain and either age or weight in normal animals over the three-month time span of the experiment. Directly after unilateral removal of the ulnar diaphysis, the principal compressive strain on the radial shaft increased by two to two and one-half times its normal value. The increased level of strain in the radius caused by ulnar ostectomy resulted in a rapid and substantial remodeling response in the radius, but three months after ulnar ostectomy, the area of bone enclosed by the periosteal perimeter of the overstrained radius approached the value for the radius and ulna together in the contralateral limb, as did the cross-sectional area of the bone tissue in the mid-shaft of that radius. Three months after unilateral ostectomy, the principal compressive strain was not significantly different in the left and right radii and approached normal values.

Animals↗
PubMed1975

Bone deformation recorded in vivo from strain gauges attached to the human tibial shaft.

A strain gauge rosette was attached to the midshaft of a man's tibia. This demonstrated that during every stride the bone surface was subjected to a number of discrete deformation cycles. During each cycle the bone was deformed from a particular direction, released at least partially and then deformed from another direction. This feature has been observed from a number of sites in experimental animals. The largest deformation occurred while the subject was running; the principal tension then reached 850 microstrain applied in line with the bone's long axis at 13 times 10-3 microstrain per second. When walking the largest deformation occurred prior to 'toe off'; compression was then the larger principal strain about minus 400 microstrain applied at 37 degrees to the bone's long axis at minus 4 times 10-3 microstrain per second. These strain values are the same order of size as those recorded from the long bones of sheep and pigs during their locomotion.

Adult↗
PubMedDate not supplied

Oxidative energy metabolism in equine tendon cells.

Hypoxia has been suggested as a possible cause of tissue degeneration and subsequent rupture in equine tendons. To determine whether low oxygen tension is likely to be detrimental to tendon cell function, experiments were designed to investigate oxidative energy metabolism in freshly isolated and cultured equine tendon cells. Freshly isolated tenocytes and cultured fibroblasts possessed activities of the mitochondrial enzyme citrate synthase similar to those of other mammalian cells, with well defined oxidative metabolism. D-[6(-14)C]-glucose oxidation was measurable in both freshly isolated and explant-derived cells. The content of adenosine triphosphate (ATP) in cultured cells was decreased by incubation with a mitochondrial respiratory uncoupler. These data demonstrate that tendon cells are capable of oxidative energy metabolism and rely upon it to maintain cellular ATP levels. Hypoxia must therefore be considered as a possible factor leading to tendon degeneration and subsequent injury.

Adenosine Diphosphate↗
PubMedDate not supplied

Bone loss during long term space flight is prevented by the application of a short term impulsive mechanical stimulus

In long term space flight, the mechanical forces applied to the skeleton are substantially reduced and are altered in character. This reduced skeletal loading results in a reduction in bone mass. Exercise techniques currently used in space can maintain muscle mass but the mechanical stimulus provided by this exercise does not prevent bone loss. By applying an external impulsive load for a short period each day, which is intended to mimic the heel strike transient, to the lower limb of an astronaut during a long term space flight (5 months), this study tests the hypothesis that the bone cells can be activated by an appropriate external mechanical stimulus to maintain bone mass throughout prolonged periods of weightlessness. A mechanical loading device was developed to produce a loading of the os-calcis similar to that observed during the heel strike transient. The device is activated by the astronaut to provide a transient load to the heel of one leg whilst providing an equivalent exercising load to the other leg. During the EUROMIR95 mission on the MIR space station, an astronaut used this device for a short period daily throughout the duration of the mission. Pre- and post-flight measurements of bone mineral density (BMD) of the os-calcis and femoral neck of the astronaut were made to determine the efficacy of the device in preventing loss of bone mineral during the mission. On the os-calcis which received the mechanical stimulus, BMD was maintained throughout the period of the flight, while it was reduced by up to 7% on the os-calcis which received no stimulus. Post-flight, BMD in both the stimulated and non-stimulated os-calcis reduces, the extent of this reduction however is less in the stimulated os-calcis. For the femoral neck, the mechanical stimulation does not produce a positive effect.

Aerospace Medicine↗
PubMedDate not supplied

Use of mesenchymal stem cells to facilitate bone regeneration in normal and chemotherapy-treated rats.

Reconstructing segmental bone defects after resection of malignant bone tumors is a long-standing clinical problem. Treatment of bone tumors such as osteosarcoma involves chemotherapy. These chemotherapeutic agents are potent inhibitors of cell division and these drugs may affect regeneration of bone from osteoprogenitor cells. It may be possible to reconstruct segmental bone defects by a tissue-engineering approach. The aim of this study was to investigate the use of mesenchymal stem cells (MSCs) in a fibrin glue carrier to enhance bone regeneration after chemotherapy. Bone marrow was harvested from young adult male rats of the Wistar strain; stem cells were isolated and expanded. Bone regeneration in normal and chemotherapy-treated rats was investigated in 1.5-mm rat femoral defects created by osteotomizing the femur and stabilizing the femoral fragments by external fixation. The osteotomy gap was left either unfilled, filled with fibrin glue alone, or filled with glue containing stem cells. Bone formation within the gap was determined by radiography, dual-energy X-ray absorptiometry, and histology. It was shown that MSCs encapsulated within fibrin glue could remain viable for up to 96 h in tissue culture. Chemotherapy significantly reduced bone formation in unfilled defects and defects filled only with fibrin glue. When MSCs were used in conjunction with fibrin glue, even in non-chemotherapy-treated rats bone formation in the gap was significantly increased. Using stem cells, the effects of chemotherapy on bone formation could be alleviated by bone formation in the gap similar to that seen in non-chemotherapy-treated animals with MSCs. These studies demonstrated that a tissue-engineering approach in patients undergoing chemotherapy may be beneficial for treating segmental bone defects after tumor resection.

Animals↗
PubMedDate not supplied

Enhancement of bone apposition to stainless steel cortical screws by surface modification using heat treatment: an experimental study.

OBJECTIVE: The purpose of the present study was to test whether the surface of stainless steel cortical screws modified by an oxidation process (heat treatment) resulted in enhancement of bone apposition as a consequence of better bone apposition to the metal surface. DESIGN: Control and heat-treated commercial cortical screws (stainless steel 316L) were inserted alternately into the tibiae of eight goats with a fixed insertion torque. Fluorochrome bone label was given during the six-week experimental period, after which the goats were killed and the extraction torque force measured. The screws and the adjacent bone were processed for histology. MAIN OUTCOME MEASURE: It was hypothesized that the heat-treated transcortical metal screws would have a greater extraction torque than untreated control screws. RESULTS: The extraction torque of the heat-treated screws was 0.59 +/- 0.06 newton-meters, which was significantly (p < 0.0001) higher (1.7-fold) than that of the control screws (0.35 +/- 0.02 newton-meters). Histomorphometric measurements demonstrated a 65 percent, significant (p < 0.05), increase in the area of fluorescence (indication of new bone deposition) adjacent to the heat-treated implant versus the control screws. CONCLUSIONS: Heat treatment of the cortical screws prior to insertion significantly increases fixation strength to the host bone in a large animal model. The clinical applicability will be to achieve bone apposition similar to that seen with titanium implants but with a stiff low-cost material.

Animals↗
PubMedDate not supplied

The effect of exercise and anabolic steroids on the mechanical properties and crimp morphology of the rat tendon.

The administration of anabolic steroids is believed to be widespread among athletes, but convincing evidence relating to the beneficial effect of such compounds on collagenous structures of the locomotor system is not available. Since it has not been possible to analyze relevant human tissue, an animal model was used to investigate the change in particular mechanical and morphological properties of rat tendon after a period of controlled exercise, with or without anabolic steroid supplementation. A significant difference (P less than 0.001) was found between the crimp angles and lengths of collagen fibrils and theoretical toe limit strains of the four groups under study. No other significant differences (P greater than 0.05) were observed. Controlled exercise and anabolic steroid administration produced the greatest change in crimp parameters and the largest theoretical toe limit strain. This implies that muscle contraction will be greater for a given stress and thus alter the normal biomechanics of limb movement. Further studies are required to determine more definitively the effects of anabolic steroids on a connective tissue such as tendon.

Achilles Tendon↗