The accuracy of volumetric bone density measurements in dual X-ray absorptiometry

New developments in dual x-ray absorptiometry (DXA) allow the performance of high precision anteroposterior (AP) and lateral scans of spinal bone mineral density (BMD, units: g/cm²) without the patient moving from the supine position. Data from both projections may be combined to give an estimate of the true volumetric bone mineral density (VBMD, units: g/cm³) of the lumbar vertebral bodies. This report presents a cadaver study designed to validate DXA measurements of volumetric bone density. Sections of whole lumbar spine were scanned in AP and lateral projections in a water tank to simulate soft tissue. Individual vertebrae were then divided to separate the vertebral body from the neural arch, and vertebral body volume was measured using the displacement of sand. The bone mineral content (BMC) of vertebral bodies and neural arches was measured by ashing at 250°C for 60 hours followed by 500°C for a further 24 hours. The results showed that DXA scanning systematically underestimated ashing data by 14% for AP BMC, 33% for vertebral body BMC, 23% for vertebral body volume, and 12% for VBMD. Despite these significant systematic errors, the DXA measurements and ashing values were highly correlated (r=0.979-0.992). The results suggested that after allowing for the systematic errors, lateral DXA parameters related closely to true BMC, volume, and VBMD.     

Splenic abscess and peritonitis in a continuous ambulatory peritoneal dialysis (CAPD) patient

A 26-year-old female was on continuous ambulatory peritoneal dialysis (CAPD) because of diabetic end-stage renal failure. She developed an acute peritonitis that relapsed repeatedly despite appropriate antibiotic treatment. Investigations showed the presence of a splenic abscess, and splenectomy and peritoneal cannula removal were required. The patient died of myocardial infarction two weeks postoperatively. This is the first recorded case of peritonitis secondary to splenic abscess in a CAPD patient. Autopsy findings suggest that the abscess developed from infection of a splenic infarct.     

Perceptions of intimidation in the psychiatric educational environment in Edmonton, Alberta.

OBJECTIVE: To examine the perceptions of intimidation in the psychiatric educational environment in Edmonton, Alberta. METHODS: We distributed a 7-point modified Likert scale questionnaire that included questions with respect to intimidation perceptions and experience in psychiatry during a 1-week period to all student interns on psychiatry rotations, residents, and teaching faculty in the 5 teaching hospitals in Edmonton. RESULTS: A total of 92 individuals responded, with response rates of 81% for faculty, 82% for residents, and 84% for students. Response rates did not differ among sites. While there were differences between site and group with respect to comparing the perceived intimidation in psychiatry with other specialties, respondents did not view psychiatry as worse than other specialties. Although, overall, women perceived intimidation as more prevalent at their sites than did men, the overall means reflect sites that are relatively free from intimidation. Faculty and student interns within sites, except for the university hospital, tended to disagree on management's approach to perceived intimidation. All groups, however, reported little personal experience and felt their sites had little tolerance for intimidators. CONCLUSIONS: Reported perceptions and personal experiences of intimidation within the psychiatric learning environment in Edmonton are low.     

Bone mineral density in professional female dancers.

OBJECTIVES: To measure the long term effects of dance training and the contribution of the timing and duration of any menstrual disruption on bone mineral density (BMD). DESIGN: Measurement of BMD in 57 premenopausal, previously professionally dance trained women and the relationship to menstrual and training history. MAIN OUTCOME MEASURES: Bone density measurements at lumbar spine and femoral neck by dual energy x-ray absorptiometry. RESULTS: The average Z score for BMD at the lumbar spine in the amenorrhoeic dancers was significantly below that for the normal population. The average Z score for BMD at the femoral neck in the eumenorrhoeic dancers was significantly above that for the normal population. There was a significant difference between the average Z score for BMD at both the lumbar spine and femoral neck between the amenorrhoeic and eumenorrhoeic dancers. Significant negative relationships were found between BMD at the lumbar spine and (1) age at menarche, (2) duration of amenorrhoea, (3) BMD at the femoral neck, and (4) the variable of ideal minus lowest weight, which was independent of amenorrhoea. No significant relationships were found between duration of oral contraceptive pill usage and BMD at either the lumbar spine or the femoral neck in eumenorrhoeic or amenorrhoeic dancers. In order to quantify the effect of a combination of these significant factors, a model of BMD was constructed using multiple regression incorporating the variables duration of amenorrhoea, age at menarche, and ideal minus lowest body weight. In this model R2 was 33.6%, in other words 33.6% of the total variation in the Z score for BMD at the lumbar spine could be accounted for by these factors. CONCLUSION: Professional female dancers with a history of delayed menarche and amenorrhoea have been identified as another group of premenopausal women potentially at risk of developing osteoporosis because of a decrease in BMD at the lumbar spine. The femoral neck in dancers with a history of amenorrhoea was partially protected from loss of BMD by virtue of being the major weight bearing site in previous dance training, and in eumenorrhoeic dancers BMD was significantly increased at this site.     

Simulated implant surgery in rabbit long bones: a descriptive study.

The objectives of this study were: (a) to observe and describe the variability of bone healing in implant receptor sites which were prepared in rabbit femurs by use of different surgical methods; and (b) to determine if the animal model which was used was suitable for the detection of differences in healing reactions in implant receptor sites which were prepared by different surgical methods. Three 3-mm-wide implant receptor sites were prepared in the right and left femurs of four large New Zealand white rabbits. The surgical parameters used in preparation of the different sites included: low speed with no irrigation (LSO); low speed with internal irrigation only (LSI); low speed with external irrigation only (LSE); high speed with no irrigation (HSO); or high speed with external irrigation only (HSE). The sites were randomized so that each animal had one of each type of site in either the right or left femur. A non-treated control site was located in each animal for comparison with experimental sites. The animals were killed at 7, 14, 21, and 28 days post-operatively. The resultant samples were fixed, embedded, sectioned, and stained with basic fuchsin and toluidine blue. The results indicated that this was probably not a suitable animal model, since no discernible differences were detected in the various healed sites.     

How much of a primary care nurse's time is spent on those with respiratory disease? A pilot study.

A pilot study was undertaken to assess the respiratory component of primary care nurses' working time. 13 nurses were interviewed and 10 completed a diary during one working week. The nurses spent a mean 6.6% of their time caring for those with respiratory disease and were of the opinion that during this time they undertook 68% of the management of long term respiratory illness in the practices. More time was spent with those with asthma than with other respiratory conditions and the nurses felt that they were appropriately trained for the tasks undertaken. However, with more training they felt that they could undertake more basic care of those patients with COPD, and more advanced care of those patients with asthma.