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Biomedical subjects

W J Gillespie

Publications and source records attributed to W J Gillespie.

At least 19 recordsLinked to original sources
PubMed1992

A comparison of elderly patients with proximal femoral fractures and a normal elderly population: a case control study.

AIM: To assess the importance of bone density and other risk factors in elderly subjects with hip fractures. METHOD: Thirty-six subjects with femoral neck fracture were compared with 72 community controls in this case control study. Variables compared included: history of falls, previous fracture, body mass index, hand grip strength, blood pressure, medication use, cigarette smoking, alcohol intake, visual acuity, age at menopause, mental status quotient, mobility index and mid thigh circumference. Bone mineral density was measured at the hip (DPA absorptiometer) in the 36 subjects with hip fracture and 36 community controls. RESULTS: Fracture patients had significantly (p < 0.01) reduced bone mineral density at femoral neck (0.64 vs 0.74 g/cm2) and trochanteric regions (0.55 vs 0.66 g/cm2). They also had significantly (p < 0.05) lower body mass index, weaker hand grip strength, smaller mid thigh circumference, reduced mobility and more previous fractures. After controlling for age and sex stepwise logistic regression identified handgrip strength, mobility status and falls in that ranking as risk factors for fracture. Bone mineral density was correlated with mobility status and grip strength. CONCLUSION: Patients with hip fracture have lower bone mineral density than controls. Mobility, grip strength and muscle bulk appear to be important in fracture aetiology and could operate either through bone density or risk of falling.

Accidental Falls↗
PubMed1992

Estimation of peak oxygen consumption from a sub-maximal half mile walk in obese females.

This study compared peak oxygen consumption estimated from a half mile sub-maximal walk test with oxygen consumption determined from a maximal treadmill test with 96 obese females. A half mile walk was completed as quickly as possible without running. Retests on 71 subjects were completed to determine the reliability of the half mile walk. Hearts rates were obtained for 15 s immediately upon completion of the walks. Stepwise regression to estimate peak VO2 was used with the following variables: walk time (TM), body weight, height, BMI, age, and heart rate (HR). The best equation was peak VO2 (ml/kg/min) = 53.23 - (1.98 x TM) - (0.32 x BMI) - (0.08 x age), r = 0.76, s.e.e. = 2.89 ml/kg/min. The mean difference between determined and estimated peak VO2 in a cross-validation group of subjects who were not included in the validation group was 0.15 ml/kg/min (n.s.), r = 0.77, s.e.e. = 3.01 ml/kg/min, E = 3.09. Reliability for time to complete the half mile walk was r = 0.87 with 0.1 min difference (n.s.). This study indicated the half mile walk to provide an accurate, reliable estimate of peak VO2 which should be useful in the clinical setting.

Adult↗
PubMed1990

Effects of age and sex on bone density at the hip and spine in a normal Caucasian New Zealand population.

We have studied a normal adult caucasian population (462 females, 264 males age range 20-84) using dual photon absorptiometry to establish patterns of bone reduction at the spine and hip. Subjects were either randomly selected from the electoral roll or volunteers. Bone mineral density reduction at the lumbar spine in females appeared to increase at 40 years and was sustained until 60 years. In males bone mineral density at the spine was preserved. The density at the hip in females decreased throughout adult life beginning before the menopause. In males bone density was preserved at the femoral neck and trochanteric region but not at Wards triangle where reduction occurred throughout life. When compared with other normal populations there was higher bone mineral density at the spine in postmenopausal New Zealand females but no significant difference at the hip.

Absorptiometry, Photon↗
PubMed1990

Economic appraisal of new technology in the absence of survival data--the case of total hip replacement.

The development of total hip replacement has reached a level at which little further improvement in pain relief or quality of life can be expected from the introduction of new prosthetic technology. Rather, it is reasonable to expect longer trouble-free prosthetic life. This paper develops a mathematical model for a comparative economic appraisal of two types of prostheses, the conventional cemented one and the new cementless one. The lack of reliable survivorship data precludes reaching definite conclusions. However, by extensive sensitivity analysis with respect to a number of cost parameters the model can be used to derive conditions under which the cementless prosthesis is more cost effective. Expert medical judgement can then be used to gage whether these conditions are likely to be satisfied. The paper highlights the importance of collecting statistically valid performance data on any new medical technology from its first introduction. Without these, its full-scale adoption will be based largely on subjective grounds rather than a proper cost benefit analysis. It finally shows how both aspects--economic modeling and scientific data collection--form part of an integrated management programme for the economic evaluation of new medical technology.

Acrylates↗
PubMed1990

Mechanisms of bone degradation in infection: a review of current hypotheses.

Bone infection in clinical practice results in loss of structural integrity, leading to complications such as fracture and implant loosening. The biology of this process has received relatively little attention. In experimental models it seems clear that both polymorphonuclear leukocytes, whose effect predominates in the early stages, and mononuclear phagocytes are capable of bone degradation. An indirect effect by stimulation of physiologic mechanisms of resorption has not been ruled out, but the evidence points to direct degradation by inflammatory cell enzymes.

Animals↗
PubMed1990

Soluble products of Staphylococcus aureus-stimulated blood mononuclear cells in enhancing polymorphonuclear leukocyte degradation of bone.

Rapid, extensive loss of infected bone implies abnormal localized inflammatory cell activity. We have demonstrated, using a live bone Ca-45 release model, that polymorphonuclear leukocytes degrade bone in a dose dependent manner. Staphylococcus aureus-stimulated blood mononuclear leukocytes release soluble products in vitro that enhance that process. Despite the usually accepted roles of osteoclasts and their blood-borne monocytic precursors in normal bone remodelling, these results indicate that considerable early pathological infected bone loss may be attributable to inflammatory polymorphonuclear leukocytes.

Animals↗
PubMed1990

Epidemiology in bone and joint infection.

The studies of community-acquired infection indicate the importance of the environment in which the host-pathogen interaction takes place. Whereas the high incidence rates at the extremes of life are compatible with a hypothesis of diminished immune competence, the varying rates of acute osteomyelitis during growth, and its predominantly metaphyseal site, suggest that further studies of the molecular biology of this rather specific infection would be revealing. Molecular biology has a role, too, in improving understanding of the epidemiology of resistance and pathogenicity in hospital-acquired infections. Although antibiotic prescription and other medical practices influence the environment profoundly, we should remember that we may be experiencing long-term trends beyond our present understanding. As more and more reconstructive bone and joint surgery is carried out, careful observational epidemiology remains a vital tool.

Arthritis, Infectious↗
PubMed1990

Infection in total joint replacement.

Although a small number of infections in total joint replacements are blood borne from distant sources, most infections appear to have been derived at operation. Strenuous attempts to reduce this risk by cleaning the air in the wound environment, coupled with prophylactic antibiotics, have reduced infection rates by an order of magnitude in a decade. During that time the potential for exchange arthroplasty in established infection has been shown, and the results are encouraging. Rigorous infection control is the key to containing this difficult and expensive problem.

Anti-Bacterial Agents↗
PubMed1989

Leg blood flow during total hip replacement under spinal or general anaesthesia.

Calf blood flow was studied using venous occlusion impedance plethysmography during 122 total hip arthroplasties. Patients were randomly allocated to receive spinal or general anaesthesia. Blood flow was measured nine times perioperatively. In the non-surgical leg, mean blood flow rose by over 50% in both groups following anaesthetic induction, remaining significantly elevated with spinal but falling back gradually to baseline with general anaesthesia. In the surgical leg, surgical manipulations produced marked falls in flow in many patients, particularly with femoral component insertion. If this occurred, hyperaemia was commonly seen with spinal anaesthesia but rarely with general anaesthesia once the joint was relocated. Venous outflow resistance rose slightly during anaesthesia in both groups, more so with general anaesthesia. In the surgical leg, marked rises occurred with surgical manipulations, but resistance fell abruptly once the joint was relocated. No clear relationship between these observations and the occurrence of deep vein thrombosis postoperatively was established.

Anesthesia, General↗
PubMed1989

Deep vein thrombosis after total hip replacement. A comparison between spinal and general anaesthesia.

The effect of hypobaric spinal anaesthesia or narcotic-halothane-relaxant general anaesthesia on the incidence of postoperative deep vein thrombosis was studied in 140 elective total hip replacements in a prospective randomised manner. Deep vein thrombosis was diagnosed using impedance plethysmography and the 125I fibrinogen uptake test, combined, in selected cases, with ascending contrast venography. The overall incidence of deep vein thrombosis was 20%. Nine patients (13%) developed deep vein thrombosis in the spinal group and nineteen (27%) in the general anaesthetic group (p less than 0.05). The incidences of proximal thrombosis and of bilateral thrombi were also less with spinal anaesthesia than with general anaesthesia. It is concluded that spinal anaesthesia reduces the risks of postoperative thromboembolism in hip replacement surgery. The presence of varicose veins, being a non-smoker and having a low body mass index were associated with an increased incidence of deep vein thrombosis.

Aged↗
PubMed1988

The incidence of cancer following total hip replacement.

We have studied the incidence of tumours at remote sites following total hip replacement: 1,358 individuals have been followed up for 14,286 person-years after operation. In the decade following implantation the incidence of tumours of the lymphatic and haemopoietic systems was significantly greater, and that of cancer of the breast, colon, and rectum, significantly less than expected. Whilst the association might be due in part to an effect of the prosthetic implants, other mechanisms, particularly drug therapy, require consideration.

Breast Neoplasms↗