Describing fluctuating indoor aerosol dust measurements with application to house dust mite allergens.

Measuring house dust mite aeroallergen concentrations is essential in understanding mite allergen exposure. Physically, the aerolized house dust mite faeces are part of indoor particulate matter. We studied the statistical ways of summarizing measurements of fluctuating mite aeroallergen exposure inside homes through indoor particulate matter. To study emissions from beddings, we measured the time-related airborne dust concentration after shaking a duvet. Analysis was performed both by a method based on the estimated mean and by a non-linear model. Twenty-eight studies reported a sum of concentrations; only one also reported the peak. In our four experiments on shaking a duvet (245 to 275 measurements each), the peak value was two to four times higher than the mean. The mean-based and non-linear models both predicted the sum of concentrations exactly. A 1% upper prediction bound and the non-linear model predicted the peak emission rate moderately well (64 to 92%, and 63 to 93%, respectively). Mean levels of indoor particulate matter measurements differ substantially from peak concentrations. The use of the mean is only sufficient to predict the sum of concentrations. We suggest that, mite aeroallergen measurements should include information on the peak as well as the mean.

Effectiveness of mite-impermeable covers: a hypothesis-generating meta-analysis.

Asthma is a heterogeneous disease. The subject of mite allergen control has evolved into a debate dominated by a Cochrane review by Gøtzsche and Johansen (Cochrane Database of Systematic Reviews, 2008, Art. No: CD001187). A not well-discussed aspect of that study is the selection by those authors of a univariate meta-analysis including various interventions. This study extends the meta-analysis by Gøtzsche and Johansen and aims to generate hypotheses on the effectiveness of various bedding interventions, including the coverage of all bedding elements. Trials were selected based on environmental criteria. The interventions were classified according to the number of barriers used. Standardized mean differences yielded the mite load, three physiological outcomes and asthma symptom scores. The influence of covariates was examined with a mixed-effect model using the metafor package for meta-analysis in R. Twelve trials included 1187 observations. The interventions included one barrier or product (six trials), two barriers or partial control (four trials) and three barriers or integral control (two trials). The exposure data showed considerable heterogeneity (I(2) = 93%). The risk of bias significantly (P = 0.04) influenced the final load, the square root of the interaction between the baseline load and the type of intervention as well (95% CI: -0.66 to -0.07 µg/g; P = 0.02). Changes in load showed similar tendencies. Health outcomes showed moderate to considerable heterogeneity (physiological outcomes I(2) = 44-94%; symptom score I(2) = 93%). A meta-regression of bedding interventions indicates that integral control most significantly reduced mite load when the load was high at baseline. The number of trials was too small to allow an appropriate examination of health outcomes. Future studies are suggested to test the hypothesis that allergic patients benefit from integral control when the baseline mite load is high.

Computed tomography of ununited neurocentral synchondrosis in the cervical spine.

The authors describe an unusual case of unilateral, nonfusion of the neural arch of the sixth cervical vertebra, documented with conventional X-ray examination and computed tomography. A brief review of other forms of congenital clefts is given and correlated with embryological findings.

An echo-free silicone elastomer block for ultrasonography.

The authors use a silicone elastomer block, rather than less-convenient water baths, to reduce echo reverberations during ultrasound examinations of superficial anatomic structures.

Monocytic leukaemia associated with myeloid metaplasia, resembling metastatic bone disease.

A case of lethal, subacute monocytic leukaemia is described in which the development of multiple sclerotic bone lesions, resembling metastases, was due to secondary myeloid metaplasia. The spectrum of leukaemic involvement of the skeleton is discussed with emphasis on sclerotic bone lesions. The differential diagnosis of other focal areas of bone sclerosis is considered.

Synovial plicae of the knee on computed tomography.

Computed tomography (CT) of the knee was performed in 160 patients following double-contrast arthrography. Seventy-five synovial folds on the medial wall of the knee joint were found, and 63 of these plicae could be considered mediopatellar plicae. In 10 of the 63 cases, long, thick mediopatellar plicae were found, which could lead to a mechanical internal derangement. Twelve synovial folds did not conform to the classic description of a mediopatellar plica. These folds probably represent synovial tissue reaction, since they were most commonly seen in patients who had undergone meniscectomy.

A comparative study of the patello-femoral joint on axial roentgenogram, axial arthrogram, and computed tomography following arthrography.

After arthrography 71 young patients with pain in the knee had a computed tomography (CT) examination. The form of the patella is classified according to the method of Wiberg [12] and on CT 50% of them do not correspond to the type described on the axial roentgenogram. The position of the patella can be examined on CT with a relaxed knee in 15 degrees of flexion. The patellar cartilage is easier to assess on CT: congruity, regularity, imbibition of contrast material and thickness are studied.

The value of computed tomography scanning in chondromalacia patellae.

Sixty seven patients with pain in the knee were studied. A compound tomography (CT) score indicating chondromalacia was devised, based on the results of CT after arthrography. This score takes account of the regularity, the congruity, and the imbibition of contrast material. Thus the patients could be divided into four groups: those who definitely have chondromalacia (++), probably (+), probably not (+/-), and definitely not (-). These results were compared with the clinical diagnosis based on clinical signs, arthroscopy, or operation. Eighteen patients had clinically proved chondromalacia, CT scored 14++, 3+ and 1+/-. Twenty nine patients had no chondromalacia, CT scored 19-, 8+/-, and 2+. Twenty patients had an uncertain clinical diagnosis. Arthrography was less accurate in detecting chondromalacia.