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Sci Rep ; 11(1): 2051, 2021 01 21.
Artigo em Inglês | MEDLINE | ID: mdl-33479334


The COVID-19 pandemic has led to widespread shortages of personal protective equipment (PPE) for healthcare workers, including of N95 masks (filtering facepiece respirators; FFRs). These masks are intended for single use but their sterilization and subsequent reuse has the potential to substantially mitigate shortages. Here we investigate PPE sterilization using ionized hydrogen peroxide (iHP), generated by SteraMist equipment (TOMI; Frederick, MD), in a sealed environment chamber. The efficacy of sterilization by iHP was assessed using bacterial spores in biological indicator assemblies. After one or more iHP treatments, five models of N95 masks from three manufacturers were assessed for retention of function based on their ability to form an airtight seal (measured using a quantitative fit test) and filter aerosolized particles. Filtration testing was performed at a university lab and at a National Institute for Occupational Safety and Health (NIOSH) pre-certification laboratory. The data demonstrate that N95 masks sterilized using SteraMist iHP technology retain filtration efficiency up to ten cycles, the maximum number tested to date. A typical iHP environment chamber with a volume of ~ 80 m3 can treat ~ 7000 masks and other items (e.g. other PPE, iPADs), making this an effective approach for a busy medical center.

Peróxido de Hidrogênio/farmacologia , Respiradores N95/virologia , Equipamento de Proteção Individual/virologia , Esterilização/métodos , COVID-19/epidemiologia , COVID-19/prevenção & controle , Reutilização de Equipamento/estatística & dados numéricos , Humanos , Respiradores N95/provisão & distribuição , Pandemias/prevenção & controle , Equipamento de Proteção Individual/provisão & distribuição , Dispositivos de Proteção Respiratória , SARS-CoV-2/isolamento & purificação , Estados Unidos/epidemiologia
medRxiv ; 2020 Apr 23.
Artigo em Inglês | MEDLINE | ID: mdl-32511480


OBJECTIVE: The COVID-19 pandemic has led to widespread shortages of personal protective equipment (PPE) for healthcare workers, including filtering facepiece respirators (FFRs) such as N95 masks. These masks are normally intended for single use, but their sterilization and subsequent reuse could substantially mitigate a world-wide shortage. DESIGN: Quality assurance. SETTING: A sealed environment chamber installed in the animal facility of an academic medical center. INTERVENTIONS: One to five sterilization cycles using ionized hydrogen peroxide (iHP), generated by SteraMist equipment (TOMI; Frederick, MD). MAIN OUTCOME MEASURES: Personal protective equipment, including five N95 mask models from three manufacturers, were evaluated for efficacy of sterilization following iHP treatment (measured with bacterial spores in standard biological indicator assemblies). Additionally, N95 masks were assessed for their ability to efficiently filter particles down to 0.3um and for their ability to form an airtight seal using a quantitative fit test. Filtration efficiency was measured using ambient particulate matter at a university lab and an aerosolized NaCl challenge at a National Institute for Occupational Safety and Health (NIOSH) pre-certification laboratory. RESULTS: The data demonstrate that N95 masks sterilized using SteraMist iHP technology retain function up to five cycles, the maximum number tested to date. Some but not all PPE could also be sterilized using an iHP environmental chamber, but pre-treatment with a handheld iHP generator was required for semi-enclosed surfaces such as respirator hoses. CONCLUSIONS: A typical iHP environment chamber with a volume of ~80 m3 can treat ~7000 masks per day, as well as other items of PPE, making this an effective approach for a busy medical center.

Adv Clin Chem ; 94: 31-84, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31952574


The purpose of this review is to describe structure and function of the multiple proteins of the coagulation system and their subcomponent domains. Coagulation is the process by which flowing liquid blood plasma is converted to a soft, viscous gel entrapping the cellular components of blood including red cells and platelets and thereby preventing extravasation of blood. This process is triggered by the minimal proteolysis of plasma fibrinogen. This transforms the latter to sticky fibrin monomers which polymerize into a network. The proteolysis of fibrinogen is a function of the trypsin-like enzyme termed thrombin. Thrombin in turn is activated by a cascade of trypsin-like enzymes that we term coagulation factors. In this review we examine the mechanics of the coagulation cascade with a view to the structure-function relationships of the proteins. We also note that two of the factors have no trypsin like protease domain but are essential cofactors or catalysts for the proteases. This review does not discuss the major role of platelets except to highlight their membrane function with respect to the factors. Coagulation testing is a major part of routine diagnostic clinical pathology. Testing is performed on specimens from individuals either with bleeding or with thrombotic disorders and those on anticoagulant medications. We examine the basic in-vitro laboratory coagulation tests and review the literature comparing the in vitro and in vivo processes. In vitro clinical testing typically utilizes plasma specimens and non-physiological or supraphysiological activators. Because the review focuses on coagulation factor structure, a brief overview of the evolutionary origins of the coagulation system is included.

Fatores de Coagulação Sanguínea/química , Fatores de Coagulação Sanguínea/fisiologia , Fibrina/fisiologia , Fibrinogênio/fisiologia , Humanos , Proteólise , Relação Estrutura-Atividade , Tripsina/fisiologia
Front Physiol ; 6: 302, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26578974


INTRODUCTION: Age-related changes in muscle mass and muscle tissue composition contribute to diminished strength in older adults. The objectives of this study are to examine if an assessment method using mobile diagnostic ultrasound augments well-known determinants of lean body mass (LBM) to aid sarcopenia staging, and if a sonographic measure of muscle quality is associated with muscle performance. METHODS: Twenty community-dwelling female subjects participated in the study (age = 43.4 ± 20.9 years; BMI: 23.8, interquartile range: 8.5). Dual energy X-ray absorptiometry (DXA) and diagnostic ultrasound morphometry were used to estimate LBM. Muscle tissue quality was estimated via the echogenicity using grayscale histogram analysis. Peak force was measured with grip dynamometry and scaled for body size. Bivariate and multiple regression analyses were used to determine the association of the predictor variables with appendicular lean mass (aLM/ht(2)), and examine the relationship between scaled peak force values and muscle echogenicity. The sarcopenia LBM cut point value of 6.75 kg/m(2) determined participant assignment into the Normal LBM and Low LBM subgroups. RESULTS: The selected LBM predictor variables were body mass index (BMI), ultrasound morphometry, and age. Although BMI exhibited a significant positive relationship with aLM/ht(2) (adj. R (2) = 0.61, p < 0.001), the strength of association improved with the addition of ultrasound morphometry and age as predictor variables (adj. R (2) = 0.85, p < 0.001). Scaled peak force was associated with age and echogenicity (adj. R (2) = 0.53, p < 0.001), but not LBM. The Low LBM subgroup of women (n = 10) had higher scaled peak force, lower BMI, and lower echogenicity values in comparison to the Normal LBM subgroup (n = 10; p < 0.05). CONCLUSIONS: Diagnostic ultrasound morphometry values are associated with LBM, and improve the BMI predictive model for aLM/ht(2) in women. In addition, ultrasound proxy measures of muscle quality are more strongly associated with strength than muscle mass within the study sample.

Healthc Manage Forum ; 23(4): 169-74, 2010.
Artigo em Inglês | MEDLINE | ID: mdl-21739818


This study evaluates the effectiveness of a performance-focused methodology for engaging multidisciplinary, frontline healthcare teams in making behavioural changes that improve patient care and health system efficiency. Results include significant declines in average length of stay in hospital and waiting time for surgery, and a dramatic increase in early patient ambulation. Performance-focused methodology using key performance indicators, targets, measurement, and ongoing feedback, supported by non-monetary incentives, can quickly improve healthcare outcomes.

Artroplastia de Quadril , Artroplastia do Joelho , Prestação Integrada de Cuidados de Saúde/organização & administração , Avaliação de Processos e Resultados em Cuidados de Saúde , Reembolso de Incentivo , Alberta , Eficiência Organizacional , Humanos , Tempo de Internação/estatística & dados numéricos , Motivação , Alta do Paciente/estatística & dados numéricos , Listas de Espera
Infect Immun ; 71(5): 2881-4, 2003 May.
Artigo em Inglês | MEDLINE | ID: mdl-12704162


The secreted Mac protein made by serotype M1 group A Streptococcus (GAS) (designated Mac(5005)) inhibits opsonophagocytosis and killing of GAS by human polymorphonuclear neutrophils. This protein also has cysteine endopeptidase activity against human immunoglobulin G (IgG). Site-directed mutagenesis was used to identify histidine and aspartic acid residues important for Mac IgG endopeptidase activity. Replacement of His262 with Ala abolished Mac5005 IgG endopeptidase activity. Asp284Ala and Asp286Ala mutant proteins had compromised enzymatic activity, whereas 21 other Asp-to-Ala mutant proteins cleaved human IgG at the apparent wild-type level. The results suggest that His262 is an active-site residue and that Asp284 and Asp286 are important for the enzymatic activity or structure of Mac protein. These Mac mutants provide new information about structure-activity relationships in this protein and will assist study of the mechanism of inhibition of opsonophagocytosis and killing of GAS by Mac.

Proteínas de Bactérias/química , Cisteína Endopeptidases/metabolismo , Imunoglobulina G/metabolismo , Fagocitose/efeitos dos fármacos , Streptococcus pyogenes/imunologia , Sequência de Aminoácidos , Ácido Aspártico , Proteínas de Bactérias/fisiologia , Sítios de Ligação , Histidina , Humanos , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Proteínas Opsonizantes/fisiologia , Streptococcus pyogenes/química , Relação Estrutura-Atividade