Barriers to vaccination service delivery within general practice: opportunity to make a sustainable difference in Aboriginal child health?

Objective: To identify behavioural barriers of service provision within general practice that may be impacting the vaccination coverage rates of Aboriginal children in Perth, Western Australia (WA). Methods: A purposive developed survey was distributed to 316 general practices across Perth and three key informant interviews were conducted using a mixed‐methods approach. Results: Of the surveyed participants (n=101), 67.4% were unaware of the low vaccination coverage in Aboriginal children; 64.8% had not received cultural sensitivity training in their workplace and 46.8% reported having inadequate time to follow up overdue child vaccinations. Opportunistic vaccination was not routinely performed by 30.8% of participants. Key themes identified in the interviews were awareness, inclusion and cultural safety. Conclusion: Inadequate awareness of the current rates, in association with a lack of cultural safety training, follow‐up and opportunistic practice, may be preventing greater vaccination uptake in Aboriginal children in Perth. Cultural safety is a critical component of the acceptability and accessibility of services; lack of awareness may restrict the development of strategies designed to equitably address low coverage. Implications: The findings of this study provide an opportunity to raise awareness among clinicians in general practice and inform future strategies to equitably deliver targeted vaccination services to Aboriginal children.     

Tire explosion injuries to the upper extremity.

Several articles have been published that bring attention to the destructive potential of tire explosions. Although the severity of tire explosion injuries to the head and neck region is well established, only one previous article has reported injuries to the upper extremity. Fourteen patients with upper extremity tire explosion injuries have been treated by us from 1980 to 1988. Each injury was caused by single-piece wheel assemblies, as opposed to multipiece wheel assemblies, which have traditionally been associated with the injury. Three representative patient reports are discussed. Prevention of this injury can be achieved by increased public awareness, formal industrial safety training, tire servicing with dedicated equipment including restraining devices or barriers, complete evaluation of wheel/tire serviceability before tire mounting, separation of servicing of single and multipiece wheels, and complete tire deflation before servicing.     

Geometric indices of bone strength are associated with physical activity and dietary calcium intake in healthy older women.

A population-based study on 1008 postmenopausal women identified that the 24% of women achieving high levels of PA and CI had 3.4-4.4% higher femoral bone strength in axial compression and 1.7-5.2% in bending than those achieving low levels, indicating that lifestyle factors influence bone strength in the proximal femur. INTRODUCTION: Extensive research has shown that increased physical activity (PA) and calcium intake (CI) decrease the rate of bone loss; however, there is little research on how these lifestyle variables affect bone geometry. This study was designed to investigate the effects of modifiable lifestyle variables, habitual PA and dietary CI, on femoral geometry in older women. MATERIALS AND METHODS: Femoral geometry, habitual PA, and dietary CI were measured in a population-based sample of 1008 women (median age+/-interquartile range, 75+/-4years) enrolled in a randomized controlled trial (RCT) of calcium supplementation. Baseline PA and CI were assessed by validated questionnaires, and 1-year DXA scans (Hologic 4500A) were analyzed using the hip structural analysis technique. Section modulus (Z), an index of bending strength, cross-sectional area (CSA), an index of axial compression strength, subperiosteal width (SPW), and centroid position, the position of the center of mass, were measured at the femoral neck (NN), intertrochanter (IT), and femoral shaft (FS) sites. These data were divided into tertiles of PA and CI, and the results were compared using analysis of covariance (ANCOVA), with corrections for age, height, weight, and treatment (calcium/placebo). RESULTS AND CONCLUSIONS: PA showed a significant dose-response effect on CSA all hip sites (p<0.03) and Z at the narrow neck and intertrochanter sites (p<0.02). For CI, there was a dose-response effect for centroid position at the intertrochanter (p=0.03). These effects were additive, such that the women (n=240) with PA in excess of 65.5 kcal/day and CI in excess of 1039 mg/day had significantly greater CSA (NN, 4.4%; IT, 4.3%; FS, 3.4%) and Z (NN, 3.9%; IT, 5.2%). These data show a favorable association between PA and aspects of bone structural geometry consistent with better bone strength. Association between CI and bone structure was only evident in 1 of 15 variables tested. However, there was evidence that there may be additive effects, whereby women with high levels of PA and CI in excess of 1039 mg/day had significantly greater CSA (NN, 0.4%; FS, 2.1%) and Z (IT, 3.0%) than women with high PA but low CI. These data show that current public health guidelines for PA and dietary CI are not inappropriate where bone structure is the health component of interest.     

Effect of high terrestrial altitude and supplemental oxygen on human performance and mood.

Sustained exposure to high terrestrial altitudes is associated with cognitive decrement, mood changes, and acute mountain sickness (AMS). Such impairment in aviators could be a safety hazard. Thirteen male soldiers, ages 19-24, ascended in 10 min from sea level to 4,300 m (simulated), and remained there 2.5 d. Four times per day, subjects completed a test battery consisting of nine cognitive tests, a mood scale, and an AMS questionnaire. During one test session per day, subjects breathed 35% oxygen instead of ambient air. Analysis revealed transient deficits on altitude day 1 for three cognitive tasks. Most tasks displayed a persistent training effect. Sick subjects' moods were more negative and their performance improvement less. On altitude day 1, oxygen administration improved performance on two cognitive tests and one mood subscale. Following rapid ascent to 4,300 m, performance is most affected during the first 8 h. Individuals affected by AMS tend to improve more slowly in performance and have more negative moods than those who feel well.     

Detection of electrocardiographic ‘left ventricular strain’ using neural nets

The use of artificial neural networks for classification of ST-T abnormalities of the electrocardiogram (ECG) was investigated. A training set of 356 lateral leads selected from 105 ECGs was visually classified as exhibiting one particular ST-T morphology (left ventricular (LV) strain) or not. Selected measurements, together with the classification, were fed as input to a three-layer software-based network during the learning process. The performance of the network was evaluated by comparing the results obtained from the network with conventional criteria, using two test sets. Set 1 comprised 63 lateral leads from 32 ECGs with ST-T changes showing atypical forms of LV strain. Set 2 consisted of 80 lateral leads from 20 ECGs containing normal and abnormal T-waves. For set 1, the network outperformed conventional criteria, having a higher sensitivity (96 per cent against 85 per cent) and specificity (67 per cent against 50 per cent). With test set 2, both network and conventional criteria were 100 per cent sensitive and 100 per cent specific. For sets 1 and 2 combined, the network had a higher overall sensitivity (97 per cent agaisst 89 per cent) and specificity (88 per cent against 82 per cent). The results suggest that neural networks may be useful in selected areas of electrocardiography, but care is required when selecting patterns for use in the training process.     

Management of sacral and perineal defects following abdominoperineal resection and radiation with transpelvic muscle flaps

PURPOSES: In this study we present our experience with treating persistent sacral and perineal defects secondary to radiation and abdominoperineal resection with or without sacrectomy. METHODS: Fifteen consecutive patients were treated with an inferiorly based transpelvic rectus abdominis muscle or musculocutaneous flap. RESULTS: Fourteen of the 15 patients achieved healing, and 7 patients had no complications. The remaining eight patients required one or more operative debridements and/or prolonged wound care to accomplish a healed wound. Our technique for the dissection and insetting of the transpelvic muscle flap is presented. CONCLUSION: The difficult postirradiated perineal and sacral wounds can be healed with persistent surgical attention to adequate debridement, control of infections, and a well-vascularized muscle flap. The most satisfying aspects for patients are the discontinuance of foul-smelling discharge, discontinuation of multiple, daily dressing changes, and reduction in the degree of chronic pain.Read at the meeting of the Midwestern Association of Plastic Surgeons, Bismarck, North Dakota, June 15 to 18, 1992.     

Restriction of the alternative pathway of human complement by intact Trypanosoma brucei subsp. gambiense.

We studied the interaction of African trypanosomes with human complement. Bloodstream forms of Trypanosoma brucei subsp. gambiense isolated from mice activated the alternative pathway of complement during a 30-min incubation in vitro. In human serum, all cells remained intact and motile during this period. C3 was detected on the surface by a direct binding assay with a monoclonal antibody which recognizes C3b and iC3b. C3 deposition could also be detected by this radioimmunoassay when parasites were incubated with purified C3. Such C3 binding was enhanced by factor B, factor D, and magnesium. Surface deposition of factor B was demonstrated both by flow immunofluorescence analysis and binding of radiolabeled factor B. C3 binding and factor B binding were inhibitable by EDTA but not by ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N' -tetraacetic acid (EGTA). The inhibited binding could be restored by addition of magnesium. No human immunoglobulin G or mouse immunoglobulin was detected on the trypanosome surface. By flow cytometry, neither human C5 nor polymerized C9 was detected on trypanosomes incubated in serum, although this assay was able to detect C5 and C9 on the surface of complement-treated human erythrocytes. Using a radioimmunoassay which measures C5b-9 in serum, we found that there was no generation of SC5b-9 in serum which had been incubated with trypanosomes. We concluded that, although trypanosomes activate the alternative pathway of complement, they are not lysed, because the cascade does not continue beyond the establishment of C3 convertase.     

Role of LFA-1, ICAM-1, VLA-4 and VCAM-1 in lymphocyte migration across retinal pigment epithelial monolayers in vitro.

The blood-retinal barrier (BRB), which is composed of the retinal pigment epithelium (RPE) and retinal vascular endothelium, normally restricts the traffic of lymphocytes into the retina. During ocular inflammatory conditions such as posterior uveitis there is a large increase in lymphocyte migration across the BRB. The differential role played by the two barrier sites, however, remains unclear. To evaluate the role of the posterior BRB, the migration of CD4+ antigen-specific T-cell line through rat RPE cell monolayers was investigated in vitro using time-lapse videomicroscopy. The adhesion molecules involved in controlling transepithelial migration across normal and interferon-gamma (IFN-gamma)-activated RPE was assessed with monoclonal antibodies directed against cell adhesion molecules. Lymphocytes were treated with antibodies specific for CD11a (alpha L subunit of LFA-1), CD18 (beta 2 subnit of the leucam family) and CD49 d (alpha 4 subnit of very late activation antigen-4, VLA-4), and the RPE with antibodies specific for CD54 (intracellular adhesion molecule-1, ICAM-1) and CD 106 (vascular cell adhesion molecule-1, VCAM-1). Migration across unstimulated RPE was inhibited by antibodies to ICAM-1 (48.6 +/- 3.5% reduction), leucocyte functional antigen-1 (LFA-1) alpha (61 +/- 5.2%) and LFA-1 beta (63.2 +/- 4.7%), but not by antibodies to VLA-4. VCAM-1 was not expressed on untreated RPE. Following activation of the RPE monolayers for 72 hr with IFN-gamma, antibodies to LFA-1 alpha, LFA-1 beta and ICAM-1 inhibited migration by 49.9 +/- 9.4%, 63.6 +/- 5.5% and 47.7 +/- 4.2% respectively. Antibodies to VLA-4 and VCAM-1 blocked migration by 21.5 +/- 8.4% and 32.3 +/- 6.2%, respectively, which correlated with the induction of VCAM-1 expression on RPE and increased migration. Under these conditions blocking both VCAM-1 and ICAM-1 reduced migration by 70.9 +/- 2.3%, which was greater than the effect of blocking either of these molecules alone. These results demonstrate that the posterior barrier of the BRB utilizes the same principle receptor-ligand pairings in controlling lymphocyte traffic into the retina as the vascular endothelium of the anterior BRB.