PubMed Health⌕ Search

Biomedical subjects

A E Goodship

Publications and source records attributed to A E Goodship.

At least 19 recordsLinked to original sources
PubMed1998

Exercise-related alterations in crimp morphology in the central regions of superficial digital flexor tendons from young thoroughbreds: a controlled study.

Injury to the core of the mid-metacarpal region of the superficial digital flexor tendon in Thoroughbred racehorses is a very frequent but poorly understood condition. It has been suggested that subclinical changes induced by galloping exercise weaken the collagen in this region of the tendon, predisposing it to rupture. The longitudinally arranged collagen fibrils in tendon follow a planar waveform, termed the crimp. Fibril bundles with a smaller crimp angle fail at a lower level of strain than those with a larger crimp angle. This study tested the hypothesis that a specific 18 month exercise programme would result in significant reduction of collagen fibril crimp angle and period length in the core region of the superficial digital flexor tendon of young Thoroughbreds (21 +/- 1 months), compared to the normal change in these parameters with age. Central region crimp angle and length were significantly lower in exercised horses than in control horses (P < 0.05). The crimp angle was significantly lower in this central region than in the peripheral region of the tendon in 4 of the 5 exercised horses, as was the crimp length in 3 of the 4 horses. The crimp angle in the peripheral region was significantly greater in exercised horses than in the controls (P < 0.05), which may indicate functional adaptation due to differing mechanical environment between the 2 tendon regions. The results of this study supported previous evidence that galloping exercise modifies normal age-related changes in crimp morphology in the core of the superficial digital flexor tendon. Such changes are indicative of microtrauma and would be detrimental to tendon strength.

Aging↗
PubMed1998

Effects of training on collagen fibril populations in the suspensory ligament and deep digital flexor tendon of young thoroughbreds.

OBJECTIVE: To determine the effect of a specific galloping exercise regimen on collagen fibril mass-average diameters (MAD) in the deep digital flexor tendon (DDFT) and suspensory ligament (SL) of young Thoroughbreds. ANIMALS: 12 Thoroughbred fillies, 21 +/- 1 (mean +/- SD) months old. PROCEDURE: 6 horses underwent a specific 18-month treadmill training program involving galloping exercise. The remaining 6 horses served as controls, undertaking low-volume walking exercise over the same period. Sections were excised from the midpoint of the DDFT and SL, and small strips were dissected from central and peripheral locations for each structure. Fibril diameters were measured from micrographs of transverse ultrathin sections, using a computerized image analysis program. An MAD value was calculated for the central and peripheral regions of the DDFT and SL for each horse. Values for both regions were compared between exercised and control horses. RESULTS: The MAD did not change significantly with exercise for either the DDFT or the SL. CONCLUSION: Loading of the DDFT as a result of this exercise regimen was not sufficient to stimulate collagen fibril hypertrophy, in keeping with current data that indicate this tendon, compared with the SL and superficial digital flexor tendon (SDFT), is subjected to low loads. Microtrauma, in terms of reduction in fibril MAD, may have occurred in the SL at a site different from that sampled. Another possibility is that, between the trot and the gallop, loading of the SL does not increase to the same extent as that of the SDFT.

Animals↗
PubMed1997

Exercise of young thoroughbred horses increases impact strength of the third metacarpal bone.

Exercise can have a profound effect on bone mass, but little is known of its effect on bone's material properties. In this experiment, our hypothesis was that a large difference in the training regimen of young thoroughbreds would produce a measurable difference in the mechanical properties of their bone material. When they were about 19 months old, eight thoroughbred racehorses were given one of two exercise regimens that lasted for 19 weeks: four horses (controls) were walked for 40 minutes a day but had no other exercise, and the remaining four (exercised) were additionally trotted for 20 minutes a day and given progressively intensive exercise on a treadmill. Mechanical testing to failure was performed on longitudinal beam specimens of the mid-diaphysis of the metacarpal. There was no difference in Young's modulus or bending strength between the two groups, although these properties varied somewhat depending on the position within the cortex from which the specimens had come. The specimens from the exercised horses had a slightly higher toughness, as measured by work (area under the load-deformation curve). They had a considerably higher impact strength. The impact strength of specimens from the outer cortex was also higher than that of those from the inner cortex in both groups. Impact strength correlated positively with the amount of microcracking produced during testing. Microcracking is related to structural and microstructural features in the bone. Increased loading caused the bone to respond in a way that enhanced its ability to microcrack and hence its toughness.

Analysis of Variance↗
PubMed1997

Age-related differences in collagen crimp patterns in the superficial digital flexor tendon core region of untrained horses.

OBJECTIVE: To measure collagen fibril crimp angles and lengths as well as collagen fibril mass-average diameters in central and peripheral regions of the superficial digital flexor tendon of wild horses, to ascertain any age-related changes in either region in the absence of imposed galloping exercise. DESIGN: Measurements from a random cull of wild horses. SAMPLE POPULATION: Superficial digital flexor tendon samples were taken from 23 wild horses ranging in age from two to ten years. PROCEDURE: Horses were divided into 'young' (< 5 years, n = 10), 'middle-aged' (5 to < 10 years, n = 9) and 'old' groups (10+ years, n = 4) and the mean crimp angle, mean crimp length and collagen fibril mass-average diameter calculated for the central region, and for the peripheral region of each group. Differences between groups and regions were analysed using two-tailed t tests. RESULTS: The crimp angle for the central region was found to decrease with age, so that in old horses it was smaller than that for the tendon periphery (P, 0.05). The crimp angle for the latter region did not alter significantly with age. Crimp period lengths and collagen fibril mass-average diameters did not show significant changes with age in either region. CONCLUSIONS: Reduction of the crimp angle in the core of the superficial digital flexor tendon occurs normally with age, as tendons of older animals would have undergone a higher number of loading cycles. It is possible that athletic training increases the frequency and/or the magnitude of high loading cycles experienced by the tendon, and may accelerate and worsen the normal load-related ageing process in the superficial digital flexor tendons of young performance horses, particularly in the central regions where lesions usually occur.

Aging↗
PubMed1997

Comparison of collagen fibril populations in the superficial digital flexor tendons of exercised and nonexercised thoroughbreds.

This study was undertaken to test the hypothesis that collagen fibrils, the submicroscopic units of strength in tendon, would hypertrophy in response to a specific defined training programme. Fibril diameters were measured in central and peripheral regions of superficial digital flexor tendon (SDFT) samples from five 18-month-old horses which underwent a subsequent 18 month training programme and 6 age- and sex-matched controls. Central region fibrils from the trained horses had a mass-average diameter (MAD) of 105.3 nm, which was significantly lower (P < 0.01) than that of 131.7 nm for the same region in the control horses. This reduction in fibril diameter in the region of tendon which is predisposed to injury was interpreted as evidence of microtrauma, as it implies the region is weakened by the training regimen. Repeated episodes of microtrauma may accumulate and eventually result in degenerative lesions and clinical tendonitis.

Aging↗
PubMed1997

The effect of exercise-induced localised hyperthermia on tendon cell survival.

Tendons that store energy during locomotion, such as the equine superficial digital flexor tendon (SDFT) and human Achilles tendon, suffer a high incidence of central core degeneration which is thought to precede tendon rupture. Although energy storage contributes to the efficiency of locomotion, tendons are not perfectly elastic and some energy is lost in the form of heat. Recent studies have shown that the central core of equine SDFT reaches temperatures as high as 45 degrees C during high-speed locomotion. In this study, we test the hypothesis that hyperthermia causes tendon cell death and results in tendon central core degeneration. Tendon fibroblasts cultured from the core of the equine SDFT were subjected to a temperature of 45 degrees C in an in vitro system for 0-180 min, and cell survival fraction was measured and compared with that for equine dermal fibroblasts and a commercial rat kidney fibroblast cell line (NRK 49F). Tendon fibroblasts were significantly more resistant to hyperthermia than NRK 49F cells after 30, 45 and 60 min of heating and significantly more resistant than dermal fibroblasts after 45 and 60 min of heating. After 10 min of heating at 45 degrees C, the tendon fibroblast cell survival fraction was 91 +/- 4%, whereas heating for 10 min at 48 degrees C resulted in a drop in the cell survival fraction to 22 +/- 4%. In conclusion, while temperatures experienced in the central core of the SDFT in vivo are unlikely to result in tendon cell death, repeated hyperthermic insults may compromise cell metabolism of matrix components, resulting in tendon central core degeneration.

Animals↗
PubMed1997

The effects of posterior fixation on internal intervertebral disc mechanics.

Posterior fixation of intervertebral discs is used to treat, and occasionally diagnose, discogenic pain since it is thought that it will reduce the internal loading of the discs in vitro. We measured the internal loading of ten intervertebral discs using stress profilometry under simulated physiological loads and then after posterior fixation. Partial discectomies were performed to simulate advanced disc degeneration and the sequence repeated. Posterior fixation had very little effect on the magnitude of the loads acting on the disc and none when disc degeneration was simulated. It did, however, reduce bulging of the anterior annulus under combined bending and compression (p < 0.03). Recent experiments in vivo have shown that discogenic pain is associated with abnormal bulging of the annulus which suggests that the clinical benefit of fixation may be due to this.

Aged↗
PubMed1997

An age-related study of morphology and cross-link composition of collagen fibrils in the digital flexor tendons of young thoroughbred horses.

The superficial digital flexor tendon is the most commonly injured tendon in the racing Thoroughbred. Despite the clinical significance of this structure, only limited data exist regarding normal age-related morphology of the tensile units, the collagen fibrils. The age at which these collagen fibrils become mature in composition and structure may be of importance. Consequently, the association of age and collagen fibril crosslink composition, diameter distribution and crimp morphology in the superficial and deep digital flexor tendons of Thoroughbreds up to and including three years of age has been studied. Replacement of immature crosslinks, peaking of the collagen fibril mass-average diameter and collagen fibril index, and stabilization of collagen crimp morphology changes supported the hypothesis that both digital flexor tendons become mature in structure by two years of age.

Aging↗
PubMed1996

In vivo stress measurement can predict pain on discography.

STUDY DESIGN: An in vivo experimental investigation of internal disc mechanics and discogenic pain. OBJECTIVES: To test the hypotheses: 1) The pattern of internal loading of intervertebral discs in vivo is similar to that measured previously in vitro; 2) stress concentrations also are found in clinically degenerate discs in vivo; and stress concentrations are associated with discogenic pain. SUMMARY OF BACKGROUND DATA: Stress concentrations corresponding to potentially painful loading patterns of the intervertebral disc and endplate have been observed in vitro. METHODS: The distribution of stress within the lumbar intervertebral discs of patients with chronic discogenic pain was measured using stress profilometry. The severity of their pain was assessed using provocative discography. RESULTS: Discogenic pain was found to be associated with anomalous loading of the posterolateral anulus (P < 0.001) and nucleus (P < 0.01). Painful discs were found to have a 38% wider posterolateral anulus (P < 0.023) than painless discs and to have a 63% lower mean nuclear stress (P < 0.017). CONCLUSIONS: Stress profilometry is an effective investigation of the mechanics of intervertebral discs in vivo. Discogenic pain is caused by changes in the pattern of loading of the posterolateral anulus or nucleus pulposus.

Adult↗
PubMed1996

Treatment of acute superficial digital flexor tendon injury in horses with polysulphated glycosaminoglycan.

Horses with acute injuries of the superficial digital flexor tendon were treated with a course of seven intramuscular injections of 500 mg of polysulphated glycosaminoglycan at four-day intervals. Clinical assessments of the lesions were made by a veterinary surgeon at the time of each injection and 14 and 28 days after the last injection. A total of 150 courses of the drug were administered and adequately completed assessment forms were returned for 80 cases. Long-term follow-up data were obtained for 19 cases. The subjective assessments by the veterinary surgeons showed that in 80 per cent of cases the drug was felt to be of value in the treatment of acute tendon injury.

Animals↗
PubMed1995

Parameters of forelimb ground reaction force in 48 normal ponies.

Recordings of forelimb ground reaction forces were made from 48 normal ponies moving at the trot, to evaluate the relationships between bodyweight, vertical ground reaction forces, the timing of individual events within the stance phase and the total contact time. There were highly significant correlations between the mean vertical ground reaction forces and bodyweight. The mean vertical ground reaction forces, corrected for bodyweight, were inversely correlated with the total contact time suggesting that higher trotting speeds may be associated with greater vertical ground reaction forces. The ponies' bodyweights were positively correlated with the contact time, implying a reduced stride frequency with increasing size. The ground reaction force events in the mid and late stance phases occurred at consistent fractions of the total stance time. The ground reaction forces and time parameters were highly symmetrical.

Animals↗
PubMed1995

Stress protection due to external fixation.

Bone is sensitive to mechanical influences. The presence of an orthopaedic device will impose constraints on the mechanical environment that may influence subsequent remodelling and repair. An Oxford External Fixator was applied to six intact ovine tibiae. The strains engendered during normal walking were then recorded from strain gauges applied to the mid-shaft of the bone. The fixator configuration was then altered such that the intact fixator bar connecting the pins was replaced with a sectioned version that did not permit load transfer through the fixator, and the strain environment re-recorded. The peak strains recorded with the intact bar were significantly lower than those recorded with the sectioned bar. This showed that the use of a fixator with an intact bar resulted in significant stress protection of the underlying bone. A fixator was then applied to both the right and left tibiae of a further six animals and the resulting strain environment and corresponding remodelling response was observed over 16 weeks. In each case one fixator was configured with an intact bar (the stress protected limb), whilst the other utilised a sectioned bar (the unprotected limb). The results showed that over this period the bone mineral content fell by 9% in the stress protected limb compared to the unprotected limp. Quantitative assessment of the bones showed that this bone loss occurred as a direct consequence of resorption on the periosteal and endosteal surfaces. In addition, strain recordings at week 16 showed that the fixator was still stress protecting the tibia.

Animals↗
PubMed1995

The response of the skeleton to physical training: a biochemical study in horses.

In this study we tested the hypothesis that exercise induces an adaptive response in the developing skeleton which may be monitored in vivo by measuring biochemical markers of bone metabolism. The effects of exercise on two biochemical markers of bone formation were determined; the carboxy-terminal propeptide of type I procollagen (PICP), and the bone-specific isoenzyme of alkaline phosphatase (BAP), and one putative marker of resorption, the pyridinoline crosslinked telopeptide domain of type I collagen (ICTP). All three markers were measured for a year in 2-year-old thoroughbred horses exercised three times a week on a treadmill, and values compared to a control group of age-matched animals. Levels of all three markers fell in both exercised and control groups over the 12-month period reflecting normal age changes. However, there were differences between groups in the pattern of this decrease. When expressed as a percentage of baseline values, BAP was higher (p < 0.05) at 2 months and both BAP and the PICP were higher at 4 months (p < 0.01 and p < 0.05, respectively) in the exercised group, reflecting an increase in bone turnover in this group in the early stages of training. PICP levels were also elevated in the exercised group at 10 months and this result indicates an increase in bone turnover at this time. The changes in ICTP were different; at 2 months, levels were higher in exercised animals than in controls, but there was no significant difference between the two groups at 4 and 6 months. After 8 months, ICTP levels in the exercised group increased returning to near baseline values at 10 months.(ABSTRACT TRUNCATED AT 250 WORDS)

Alkaline Phosphatase↗
PubMed1995

Age related changes in biochemical markers of bone metabolism in horses.

Biochemical markers of bone metabolism were analysed in serum samples obtained from 60 horses with no history of orthopaedic disease (age 3 months-20 years). Serum levels of the carboxyterminal propeptide of type I procollagen (PICP), a marker of bone formation and the pyridinoline cross linked telopeptide domain of type I collagen (ICTP), a putative marker of bone resorption, were measured by radioimmunoassay (RIA). Serum levels of the bone specific isoenzyme of alkaline phosphatase (BALP), another marker of bone formation, were measured by a wheatgerm agglutinin affinity (WGA) method. Total alkaline phosphatase levels were also determined. Serum levels of PICP were significantly correlated with bone ALP (r = 0.78, P < 0.0001) and ICTP (r = 0.87, P < 0.0001). ICTP levels also correlated significantly with bone ALP (r = 0.81, P < 0.0001). However, total alkaline phosphatase did not correlate significantly with PICP, ICTP and BALP in horses over 1 year of age. There was an inverse correlation between serum levels of all biochemical markers and age of animals, with the most significant changes seen over the first 2 years. In animals less than 1 year of age, the reference ranges (mean +/- s.d. 1.96) were as follows: PICP 1216-2666 micrograms/l, ICTP 13.8-26.7 micrograms/l, bone ALP 134-288 u/l and total ALP 223-498 u/l. In 2-year-olds, the equivalent reference ranges were: PICP 550-1472 micrograms/l, ICTP 7.96-22.8 micrograms/l, bone ALP 32.7-125 u/l and total ALP 134-238 u/l.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1994

Exercise-induced hyperthermia as a possible mechanism for tendon degeneration.

Mathematical modelling of tendon thermodynamics predicted that the temperature of the central core of the equine superficial digital flexor tendon would plateau at 11 degrees C above the tendon surface temperature during a sustained gallop. A mean temperature differential (between tendon core and surface) of 5.4 (S.E. +/- 1.0) degrees C was demonstrated in vivo in four horses. Peak intra-tendinous temperatures in the range 43-45 degrees C were recorded. Temperatures above 42.5 degrees C are known to result in fibroblast death in vitro [Hall (1988) Radiobiology for the Radiologist, 3rd Edn., pp. 294-329]. These in vivo recordings provide a possible aetiology for the degenerative changes that are observed in the central core of tendons in both equine and human athletes.

Achilles Tendon↗