Effectiveness of portable air filtration on reducing indoor aerosol transmission: preclinical observational trials.

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.

The effects of denture status on nutrition.

In Part I of this study, the Human Nutrition Research Center of the United States Department of Agriculture's Nutritional Status Study (NSS) of 691 independently living elderly people aged 60-98 found that poor dietary quality was associated with low educational attainment, low median family income, and self-report of partial or full dentures. In Part II, further analysis was conducted on a random subsample of 181 subjects who were examined and divided into four groups according to dentate status: two dentures, one denture, partial dentures, and teeth. In this subgroup, significant correlations were found between the quality of nutrient intake and the degree of edentulousness. Analysis of 53 nutrients plus calories from three-day food records showed a significantly higher nutritional quality of the diet in dentate volunteers than in the other groups. This difference was approximately 20% for 19 nutrients, bringing some nutrients (such as calcium) below the RDA for this age group. Although direct correlations cannot be made with actual nutritional status, the introduction of dentures could further compromise the precarious nutritional intake of the elderly population. With this in mind, dentists need to consider carefully the importance of their elderly patients maintaining at least some natural dentition and should provide adequate information on nutritional adaptations to dentures.

Combining free flap reconstruction and craniofacial prosthetic technique for orbit, scalp, and temporal defects.

OBJECTIVES: To identify factors leading to successful application of prosthetic techniques following free flap reconstruction of the orbit, scalp, and temporal region. STUDY DESIGN: Retrospective review. METHODS: Twenty-eight patients who underwent free flap reconstruction for defects of these regions between 1989 and 1996 were reviewed for clinical parameters, flap loss, patient survival, and implant loss rate. Prosthetic usage rates were compared before and after introduction of a site-specific reconstructive algorithm. RESULTS: Free flap success rate was 93%, whereas osseointegrated implant loss rate was 11%. In addition to implants, a reconstructive strategy that provided thin, vascular tissue between bone and skin, a flat platform in the temporal region, and preservation of orbital cavity depth led to increased prosthetic usage. CONCLUSIONS: Craniofacial prosthetic techniques can significantly augment the results of free flap surgery for the orbit, scalp, and temporal region. Successful combination of these techniques requires a site-specific surgical approach.

Endoscopic facial surgery.

The emergence of endoscopically assisted cosmetic surgery has been very rapid. Public demand has burgeoned this trend resulting in the widespread use of these techniques prior to their proven efficacy. Fortunately, the results to date are favorable. The endoscopic brow and forehead lift appear to be as reliable as the open coronal approach while inflicting less incisional morbidity and decreased postoperative recovery time. This combination of decreased morbidity and post surgical discomfort have led to increased patient acceptance of browlifting. The soft-tissue orbital complex is composed of the eyebrow, upper and lower eyelids, and the malar prominence. When used in conjunction with blepharoplasties, the endoscopic browlift and midfacial suspension dramatically improve the appearance of the eye when compared to blepharoplasty alone. The applied surgical anatomy, indications, and operative technique used in endoscopic upper facial rejuvenation are detailed. Surgeons who are not utilizing the endoscopic techniques are encouraged to do so when repositioning the eyebrow and malar prominence would improve the aesthetic result.

The significance of positive margins (known and unknown) at the conclusion of Mohs surgery in the orbital region.

The Mohs fresh tissue technique has provided a high rate of cure in cases of malignant tumors in the orbital region. However, in some patients, tumor may persist after Mohs surgery if margins are falsely negative or if the Mohs surgeon elects to terminate the procedure with known positive margins. We report six patients who had residual tumor present in the periorbital region after Mohs surgery. These patients have a serious prognosis associated with subsequent morbidity. Accurate communication between the Mohs surgeon and subsequent treating surgeons, combined with aggressive tumor management, may help to minimize morbidity and improve mortality.

Esthetic refinements in forehead flap nasal reconstruction.

OBJECTIVE: To identify refinements in forehead flap nasal reconstruction that consistently provide better esthetic and functional results. DESIGN: Case series of patients undergoing forehead flap nasal reconstruction from July 1, 1987, to May 31, 1994. SETTING: University hospital ambulatory surgery department. PATIENTS: Thirty-two patients with various nasal defects. INTERVENTIONS: Modifications of currently accepted techniques of paramedian forehead flap nasal reconstruction, namely, flap harvest and contouring, W-plasty closure of the superior forehead donor site, and creation of soft-tissue triangles. The principles of open-structure rhinoplasty are incorporated into cartilaginous reconstruction of the nasal tip and columella. The alar rim is reconstructed with cartilage grafts placed at the nasal rim. MAIN OUTCOME MEASURES: Esthetic and functional results of nasal reconstruction were subjectively graded by three otolaryngologists (V.C.Q., D.A.S., and M.F.R.) and the patients. RESULTS: Improved esthetic and functional nasal reconstruction. The most common nasal subunits reconstructed were as follows: ala, 27 patients (84%); side-wall, 22 patients (69%); dorsum, 18 patients (56%), and tip, 15 patients (47%). The esthetic results ranged from average to excellent (3 to 5 on a scale of 5), the functional results ranged from improved to much improved over preoperative breathing (4 to 5). Two patients required unplanned surgical revisions. Forty-seven percent of patients chose to undergo dermabrasion. Five patients required postoperative intradermal injection of triamcinolone acetonide (Kenalog). Three patients required preoperative tissue expansion. Flap or graft loss, infection, or hematoma did not occur. CONCLUSIONS: The predictability of the techniques in providing excellent results in patients undergoing nasal reconstruction decreases the need for revision procedures and helps the patient and the surgeon achieve the desired outcome.

Anion-exchange high-performance liquid chromatography with post-column detection for the analysis of phytic acid and other inositol phosphates.

The use of gradient anion-exchange HPLC, with a simple post-column detection system, is described for the separation of myo-inositol phosphates, including "phytic acid" (myo-inositol hexaphosphate). Hexa-, penta-, tetra-, tri- and diphosphate members of this homologous series are clearly resolved within 30 min. This method should facilitate analysis and quantitation of "phytic acid" and other inositol phosphates in plant, food, and soil samples.

Semipermeable-surface reversed-phase media for high-performance liquid chromatography.

Polyoxyethylene was both adsorbed hydrophobically (through the use of non-ionic surfactants) and covalently bonded to reversed-phase high-performance liquid chromatographic packings, thereby establishing a semipermeable hydrophilic layer over the alkylsilane surface. This layer restricts proteins from adsorbing to the alkylsilane phase while permitting penetration and chromatographic separation of small molecules. Biological fluids containing low-molecular-weight analytes may be injected directly, without sample pretreatment or the use of micellar eluents. In the case of adsorbed coatings, surfactant loading was determined primarily by the surface area (over the reversed phase) occupied by the polyoxyethylene head group. Semipermeability of the hydrophilic layer was demonstrated by observing changes in retention of both small molecules and proteins with increasing eluent ionic strength. Coated column stability was evaluated with regard to cumulative eluent volume and repeated serum injections.

Relationships between human cataracts and environmental radiant energy. Cataract formation, light scattering and fluorescence.

This preliminary report has two parts. The first is based upon data obtained from a group of cataract patients in southern Florida (USA) with the object of relating the types of cataracts removed to their personal background and their protein biochemistry. Intra-capsular cataract surgery patients at the Venice Eye Clinic (Florida) were interviewed, and their extracted lenses were classified. The parameters were: age, place of residency, occupation, medical and family history and indoor/outdoor activity. Subcapsular cataracts were found mainly in the youngest patients and in those who were in Florida the least. Mixed cataracts predominated in the oldest patients, while non-nuclear cataracts were associated most with outdoor activity. Water-insoluble protein was elevated in nuclei of lenses with nuclear opacities. Soluble proteins in the nuclei of nuclear cataracts had increased levels of voided (heavy) protein, beta-crystallins, and less than 20 Kd peptides. The above changes were enhanced in brunescent cataracts. In lenses with cortical opacities, only increased size heterogeneity in the beta-crystallin region was observed. The second part of this report is based upon direct measurements of the optical properties of freshly extracted intra-capsular cataracts obtained in Rochester, New York (USA). The purpose was to attempt to learn the relative contributions that absorption, scattering, and fluorescence make toward obscuring vision. A general conclusion is that the shorter wavelengths of radiant energy in environmental lighting influence the above-stated optical properties the most, and thus appear to be the major contributors to obscured vision.

Synthesis of a non-porous, polystyrene-based strong anion-exchange packing material and its application to fast high-performance liquid chromatography of proteins.

Adsorbed coating technology has been used to produce a strong anion-exchange stationary phase on 3-micron non-porous poly(styrene-divinylbenzene) particles. In order to take full advantage of the excellent kinetic properties of the resultant packing material, small columns of 5 mm X 6 mm I.D. were used. These columns were pressure- and pH-stable and allowed protein separations to be made in less than 1 min at ambient temperature.

Poly(styrene-divinylbenzene)-based strong anion-exchange packing material for high-performance liquid chromatography of proteins.

An adsorbed polyethyleneimine coating was applied to sulfonated macroporous, microparticulate poly(styrene-divinylbenzene). The chemical, physical and chromatographic properties of the resulting strong anion-exchange packing material were thoroughly characterized. The dynamic load capacity of the experimental packing was comparable to that of large-pore diameter silica. Good recoveries of protein mass and enzyme activity were achieved. The new column withstood a variety of cleaning procedures and prolonged exposure to aqueous base. The retention times on the polystyrene-based column were similar to those on a silica and a commercial, polymeric, strong anion-exchange column. Chromatographic resolution of the new packing material was equal or superior to that provided by the other two packings.

Factors contributing to intrinsic loading capacity in silica-based packing materials for preparative anion-exchange protein chromatography.

Properties of the matrix and stationary phase which affect the intrinsic loading capacity of silica-based packing materials for preparative anion-exchange chromatography of proteins were investigated. Polyethyleneimine-coated controlled porosity glass beads ranging from 100 to 2000 A in pore diameter were used to evaluate the effects of pore diameter and surface area. Protein binding was found to depend on accessible, rather than total, support surface area. Consequently, wide-pore, high surface area media provide maximum intrinsic loading capacity. Increasing the number of positively charged sites on the stationary phase by increased coating or by quaternization of amines increases hemoglobin-binding capacity.

Stationary phase contributions to retention in high-performance anion-exchange protein chromatography: ligand density and mixed mode effects.

Several anion-exchange stationary phases (based on polyethyleneimine-coated silica) were synthesized so as to vary in ligand density and hydrophobicity. These materials were first examined for hemoglobin-binding capacity and then evaluated chromatographically. Protein binding, retention and resolution increased concomitantly with ligand density. Ferritin (molecular weight 440,000) could not be eluted from the more highly-charged surfaces, but was desorbed from a low ligand density support. The above parameters also varied with the hydrophobic character of the stationary phase. Retention and resolution increased as more hydrophobic moieties were added. Data from a non-ionic hemoglobin-binding assay correlated reasonably well with anticipated matrix hydrophobicities. Possible explanations and applications of the observed phenomena are discussed.