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BACKGROUND: While the range of possible transmission pathways of severe acute respiratory syndrome coronavirus-2 in various settings has been investigated thoroughly, most authorities have recently acknowledged the role of aerosol spread in its transmission, especially in indoor environments where ventilation is poor. Engineering controls are needed to mitigate aerosol transmission in high-risk settings including hospital wards, classrooms and offices. AIM: To assess the effectiveness of aerosol filtration by portable air cleaning devices with high-efficiency particulate air filters used in addition to a standard building heating ventilation and air conditioning (HVAC) system. METHODS: Test rooms, including a single-bed hospital room, were filled with test aerosol to simulate aerosol movement. Aerosol counts were measured over time with various portable air cleaning devices and room ventilation systems to quantify the overall aerosol clearance rate. FINDINGS: Portable air cleaning devices were very effective for removal of aerosols. The aerosols were cleared five times faster in a small control room with portable air cleaning devices than in the room with HVAC alone. The single-bed hospital room had an excellent ventilation rate (∼14 air changes per hour) and cleared the aerosols in 20 min. However, with the addition of two air cleaning devices, the clearance time was three times faster. CONCLUSIONS: Inexpensive portable air cleaning devices should be considered for small and enclosed spaces in healthcare settings, such as inpatient rooms and personal protective equipment donning/doffing stations. Portable air cleaning devices are particularly important where there is limited ability to reduce aerosol transmission with building HVAC ventilation.

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Patients suffering from neurogenic intermittent claudication secondary to lumbar spinal stenosis have historically been limited to a choice between a decompressive laminectomy with or without fusion or a regimen of non-operative therapies. The X STOP Interspinous Process Distraction System (St. Francis Medical Technologies, Concord, Calif.), a new interspinous implant for patients whose symptoms are exacerbated in extension and relieved in flexion, has been available in Europe since June 2002. This study reports the results from a prospective, randomized trial of the X STOP conducted at nine centers in the U.S. Two hundred patients were enrolled in the study and 191 were treated; 100 received the X STOP and 91 received non-operative therapy (NON OP) as a control. The Zurich Claudication Questionnaire (ZCQ) was the primary outcomes measurement. Validated for lumbar spinal stenosis patients, the ZCQ measures physical function, symptom severity, and patient satisfaction. Patients completed the ZCQ upon enrollment and at follow-up periods of 6 weeks, 6 months, and 1 year. Using the ZCQ criteria, at 6 weeks the success rate was 52% for X STOP patients and 10% for NON OP patients. At 6 months, the success rates were 52 and 9%, respectively, and at 1 year, 59 and 12%. The results of this prospective study indicate that the X STOP offers a significant improvement over non-operative therapies at 1 year with a success rate comparable to published reports for decompressive laminectomy, but with considerably lower morbidity.

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A model system, consisting of bovine serum albumin, lysozyme and the cation exchanger S Sepharose FF, was used to investigate multicomponent protein adsorption to ion exchangers. Two models, one based on a complete absence of competition between adsorbing molecules and the other a competitive model, based on the assumption that all adsorption sites are available to both proteins, have been compared to experimental results. Evidence for competitive adsorption was seen in experiments in which breakthrough curves and the profiles of adsorbed proteins in packed beds were determined. However, although the results for packed-bed experiments were more closely predicted by the fully competitive model, some discrepancies were found suggesting that when considering multicomponent protein adsorption to ion exchangers it may also be necessary to take account of factors such as the molecular size of the adsorbing proteins and any potential inter-protein interactions, factors which may hinder the development of a general model of multicomponent protein adsorption to ion exchangers.

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Compositae dermatitis occurred in a 9-year-old boy with a strong personal and family history of atopy. Positive patch test reactions were 2+ for dandelion (Taraxacum officinale), false ragweed (Ambrosia acanthicarpa), giant ragweed (Ambrosia trifida), short ragweed (Ambrosia artemisifolia), sagebrush (Artemisia tridentata), wild feverfew (Parthenium hysterophorus), yarrow (Achillea millifolium), and tansy (Tanacetum vulgare) and 1+ for Dahlia species and English ivy (Hedera helix). Patch tests were negative for another 30 plants, including cocklebur (Xanthium strumarium), dog fennel (Anthemis cotula, fleabane (Erigeron strigosus), sneezeweed (Helenium autumnale), and feverfew (Tanacetum parthenium). The eruption resembled atopic dermatitis morphologically but was prominent on the palms and face and dramatically spared the area of the boy's feet covered by his shoes. The condition has always been seasonal, worsening in summer, especially July, and it clears on avoidance of contact. This case is believed to represent a contact dermatitis to oleoresins of Compositae plants; inhalants as a cause of systemic aggravation are not likely to be important in this patient.

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