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1.
J Appl Microbiol ; 131(5): 2212-2222, 2021 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-33864329

RESUMEN

AIMS: To investigate the binding of the antimicrobial compound 8-hydroxyquinoline (8HQ) to a material interface and to determine whether immobilization affects the antibacterial efficacy. METHODS AND RESULTS: The 8HQ derivative 5-carboxy-8-hydroxyquinoline (5C8HQ) was attached to silica beads through amide bond coupling at the carboxyl moiety of 5C8HQ. Attachment of 5C8HQ was confirmed using a combination of mass spectrometry, thermogravimetric analysis, colorimetric testing and Soxhlet extraction. Computational modelling results indicated that this substitution did not compromise the active sites on the molecule, whereas other positions on the ring system could potentially inhibit antimicrobial activity. The antibacterial effect of 8HQ and the 5C8HQ-modified silica complex against Escherichia coli 15597 (ATCC® 25922) and Staphylococcus aureus (ATCC 25923) was evaluated. CONCLUSIONS: The test results show that the immobilized 8HQ continues to exhibit antibacterial activity, however, quantifying the efficacy compared to free 8HQ bears further investigation. The expected antibacterial mechanism requires that the metal chelation site of 8HQ be retained and available after attachment to a surface. The retention of antibacterial activity after surface bonding represents a novel mechanism of action not previously reported. SIGNIFICANCE AND IMPACT OF THE STUDY: Recent changes in regulations due to environmental concerns prompted many companies and organizations to explore antimicrobial treatments that are chemically bound to the product. Chemically bonding biocidal compounds to a surface limits environmental release; however, molecular mechanisms that drive antibacterial activity when compounds are immobilized are limited. The results reported here demonstrate that the 8HQ reactive site retains antibacterial efficacy even after covalent attachment to a surface. This approach supersedes other antimicrobial treatments where the active component is gradually released from the material surface in order to elicit antimicrobial effects. This specific antibacterial activity of bound 8HQ represents a novel mechanism of action not previously reported, and a potential conduit to a new class of bound antimicrobial materials.


Asunto(s)
Oxiquinolina , Staphylococcus aureus , Antibacterianos/farmacología , Escherichia coli , Pruebas de Sensibilidad Microbiana
2.
Phys Rev Lett ; 122(1): 015003, 2019 Jan 11.
Artículo en Inglés | MEDLINE | ID: mdl-31012647

RESUMEN

Contemporary models of bounded plasmas assume that the target plasma electron temperature far exceeds the temperature of the cold electrons emitted from the target, T_{emit}. We show that when the sheath facing a collisional plasma becomes inverted, the target plasma electron temperature has to equal T_{emit} even if the upstream plasma is hotter by orders of magnitude. This extreme cooling effect can alter the plasma properties and the heat transmission to thermionically emitting surfaces in many applications. It also opens a possibility of using thermionic divertor plates to induce detachment in tokamaks.

3.
Indoor Air ; 27(5): 988-1000, 2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28303606

RESUMEN

Fluorescent particles can be markers of bioaerosols and are therefore relevant to nosocomial infections. To date, little research has focused on fluorescent particles in occupied indoor environments, particularly hospitals. In this study, we aimed to determine the spatial and temporal variation of fluorescent particles in two large hospitals in Brisbane, Australia (one for adults and one for children). We used an Ultraviolet Aerodynamic Particle Sizer (UVAPS) to identify fluorescent particle sources, as well as their contribution to total particle concentrations. We found that the average concentrations of both fluorescent and non-fluorescent particles were higher in the adults' hospital (0.06×106 and 1.20×106  particles/m3 , respectively) than in the children's hospital (0.03×106 and 0.33×106  particles/m3 , respectively) (P<.01). However, the proportion of fluorescent particles was higher in the children's hospital. Based on the concentration results and using activity diaries, we were able to identify sources of particle production within the two hospitals. We demonstrated that particles can be easily generated by a variety of everyday activities, which are potential sources of exposure to pathogens. Future studies to further investigate their role in nosocomial infection are warranted.


Asunto(s)
Aerosoles/análisis , Microbiología del Aire , Contaminación del Aire Interior/análisis , Infección Hospitalaria/transmisión , Fluorescencia , Hospitales/clasificación , Australia , Monitoreo del Ambiente , Factores de Tiempo
4.
Indoor Air ; 25(5): 462-74, 2015 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-25346039

RESUMEN

There is an ongoing debate about the reasons for and factors contributing to healthcare-associated infection (HAI). Different solutions have been proposed over time to control the spread of HAI, with more focus on hand hygiene than on other aspects such as preventing the aerial dissemination of bacteria. Yet, it emerges that there is a need for a more pluralistic approach to infection control; one that reflects the complexity of the systems associated with HAI and involves multidisciplinary teams including hospital doctors, infection control nurses, microbiologists, architects, and engineers with expertise in building design and facilities management. This study reviews the knowledge base on the role that environmental contamination plays in the transmission of HAI, with the aim of raising awareness regarding infection control issues that are frequently overlooked. From the discussion presented in the study, it is clear that many unknowns persist regarding aerial dissemination of bacteria, and its control via cleaning and disinfection of the clinical environment. There is a paucity of good-quality epidemiological data, making it difficult for healthcare authorities to develop evidence-based policies. Consequently, there is a strong need for carefully designed studies to determine the impact of environmental contamination on the spread of HAI.


Asunto(s)
Microbiología del Aire , Infección Hospitalaria/transmisión , Infecciones Bacterianas/transmisión , Humanos , Control de Infecciones , Micosis/transmisión , Ventilación/instrumentación
5.
J Hosp Infect ; 132: 133-139, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36309203

RESUMEN

BACKGROUND: Mycobacterium abscessus (MABS) group are environmental organisms that can cause infection in people with cystic fibrosis (CF) and other suppurative lung diseases. There is potential for person-to-person airborne transmission of MABS among people with CF attending the same care centre. Ultraviolet light (band C, UV-C) is used for Mycobacterium tuberculosis control indoors; however, no studies have assessed UV-C for airborne MABS. AIM: To determine whether a range of UV-C doses increased the inactivation of airborne MABS, compared with no-UVC conditions. METHODS: MABS was generated by a vibrating mesh nebulizer located within a 400 L rotating drum sampler, and then exposed to an array of 265 nm UV-C light-emitting diodes (LED). A six-stage Andersen Cascade Impactor was used to collect aerosols. Standard microbiological protocols were used for enumerating MABS, and these quantified the effectiveness of UV-C doses (in triplicate). UV-C effectiveness was estimated using the difference between inactivation with and without UV-C. FINDINGS: Sixteen tests were performed, with UV-C doses ranging from 276 to 1104 µW s/cm2. Mean (±SD) UV-C effectiveness ranged from 47.1% (±13.4) to 83.6% (±3.3). UV-C led to significantly greater inactivation of MABS (all P-values ≤0.045) than natural decay at all doses assessed. Using an indoor model of the hospital environment, it was estimated that UV-C doses in the range studied here could be safely delivered in clinical settings where patients and staff are present. CONCLUSION: This study provides empirical in-vitro evidence that nebulized MABS are susceptible to UV-C inactivation.


Asunto(s)
Mycobacterium abscessus , Mycobacterium tuberculosis , Humanos , Rayos Ultravioleta , Aerosoles y Gotitas Respiratorias , Desinfección/métodos
6.
Proc Inst Mech Eng H ; 225(1): 38-47, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21381486

RESUMEN

It has previously been reported that motion of the scapula varies for subjects with shoulder joint pathologies and is different from that of normal subjects. In this study, an electromagnetic tracking device was used to measure the three-dimensional scapula motion of nine patients with Bayley-Walker (B-W) reverse anatomy joint replacements. The data were then compared to scapula kinematics of 12 normal subjects with no known shoulder pathology. The scapula kinematics for each subject was determined and a regression analysis to find the mean scapula lateral rotation (SLR) for B-W and normal subjects was performed. The regression model which showed the highest change compared to normal was identified and was used in the biomechanical shoulder model to predict the glenohumeral joint contact force. A high variability of the scapula kinematics was observed, with some subjects having a maximum SLR smaller than that of the normal subjects and some similar to the normal subjects. It was found that scapula may move in such a way to keep the deltoid length at its optimum. The change in the scapula kinematics affected the predicted joint force and its point of application. Hence, knowledge of scapular kinematics is essential for realistic modelling of implanted shoulders.


Asunto(s)
Prótesis Articulares , Articulación del Hombro/fisiopatología , Articulación del Hombro/cirugía , Anciano , Anciano de 80 o más Años , Fenómenos Biomecánicos , Ingeniería Biomédica , Femenino , Humanos , Masculino , Persona de Mediana Edad , Modelos Biológicos , Rango del Movimiento Articular , Rotación , Escápula/fisiopatología , Articulación del Hombro/patología
7.
J Exp Med ; 175(6): 1443-7, 1992 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-1375260

RESUMEN

Murine bone marrow Lin-, Ly6A/E+ cells have been fractionated on the basis of rhodamine123 retention into Rh123med/hi and Rh123lo subpopulations. These populations have different responses to hemopoietic growth factors with respect to in vitro colony formation. Cells from either fraction were not stimulated by only granulocyte-colony-stimulating factor (G-CSF), granulocyte/macrophage colony-stimulating factor (GM-CSF), macrophage colony-stimulating factor (M-CSF), interleukins 1 and 6 (IL-1 and -6), or leukemia inhibitory factor (LIF) alone. The Rh123med/hi, but not the Rh123lo fraction, contained cells that could be stimulated by either stem cell factor (SCF) or IL-3 alone. When combinations of growth factors were added, the Rh123med/hi fraction produced more colonies, and responded to a wider range of factor combinations than the Rh123lo population. When tested in vivo, both populations contained no detectable day 8 colony-forming unit-spleen (CFU-S), and similar frequencies of day 13 CFU-S. When transplanted into lethally irradiated recipients (100 cells/recipient), significant numbers of donor cells (67-73%) were found in the peripheral blood of Rh123lo recipients. Both myeloid and lymphoid cells were of donor origin. By comparison, the Rh123med/hi population produced recipients with 1-2% donor cells in peripheral blood, the majority of which were lymphoid.


Asunto(s)
Antígenos Ly/análisis , Factores de Crecimiento de Célula Hematopoyética/farmacología , Células Madre Hematopoyéticas/citología , Proteínas de la Membrana/análisis , Animales , Células de la Médula Ósea , Separación Celular , Ensayo de Unidades Formadoras de Colonias , Citometría de Flujo , Colorantes Fluorescentes , Factor Estimulante de Colonias de Granulocitos/farmacología , Factor Estimulante de Colonias de Granulocitos y Macrófagos/farmacología , Inhibidores de Crecimiento/farmacología , Células Madre Hematopoyéticas/efectos de los fármacos , Interleucina-1/farmacología , Interleucina-3/farmacología , Interleucina-6/farmacología , Factor Inhibidor de Leucemia , Linfocinas/farmacología , Factor Estimulante de Colonias de Macrófagos/farmacología , Ratones , Ratones Endogámicos C57BL , Ratones Endogámicos , Fenotipo , Rodamina 123 , Rodaminas , Factor de Células Madre
8.
J Exp Med ; 148(6): 1468-77, 1978 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-309918

RESUMEN

Spleen colonies produced by transplanting lethally irradiated mice with either 12 day fetal liver or adult bone marrow cells were found to contain B- lymphocyte colony-forming cells (BL-CFC) . The proportion of BL-CFC positive spleen colonies did not increase substantially between 8 and 14 days after transplantation, the range being 18-45 percent. However, the absolute number of BL-CFC per spleen colony varied considerably (between 1 and 10,318), although the majority of colonies contained less than 200 BL-CFC. Irrespective of the time after transplantation, smaller spleen colonies were found to have a higher frequency of BL-CFC than larger spleen colonies. To determine the possible clonal origin of BL-CFC from spleen colony- forming unit (CFU-S), CBA mice were injected with equal numbers of CBA and CBA T(6)/T(6) fetal liver or adult bone marrow cells. Analysis of 7-15-day spleen colonies demonstrated that 90 percent were either exclusively T(6) positive or T(6) negative and approximately equal numbers ofboth colony types were observed. B-lymphocyte colonies were grown and successfully karyotyped from 19 spleen colonies. When compared with the original spleen colony karyotype the B-lymphocyte colony cells karyotype was identical in all 19 cases. In 3 of the 19 colonies analyzed a mixture of T(6) positive and T(6) negative karyotypes was present and identical proportions of the karyotypes were present in the pooled B-lymphocyte colony cells and spleen colony cells. The data indicate that the B-lymphocyte colony-forming cells detected in spleen colonies are genuine members of the hemopoietic clone derived from the initiating hemopoietic stem cell (CFU-S).


Asunto(s)
Linfocitos B/inmunología , Células Clonales/inmunología , Células Madre Hematopoyéticas/inmunología , Bazo/citología , Animales , Células de la Médula Ósea , Células Cultivadas , Femenino , Células Madre Hematopoyéticas/citología , Cariotipificación , Hígado/embriología , Masculino , Ratones , Ratones Endogámicos CBA , Técnicas de Cultivo de Órganos , Receptores de Antígenos de Linfocitos B/análisis
9.
J Exp Med ; 174(6): 1617-27, 1991 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-1683894

RESUMEN

A new, numerically minute population of cells representing the earliest T precursor cells in the adult mouse thymus has recently been isolated. This population has been shown to be similar to bone marrow hemopoietic stem cells in surface antigenic phenotype and to express moderate levels of CD4. We now show, by fluorescence-activated cell sorting and intrathymic transfer to irradiated mice, that this apparently homogeneous population differs from multipotent stem cells in expressing the surface stem cell antigen 2 (Sca-2), that it differs from most early B lineage cells in lacking B220 and class II major histocompatibility complex expression, and that it binds rhodamine 123 like an activated rather than a quiescent cell. Irradiated recipient mice differing at the Ly 5 locus were used to compare the developmental potential of these early intrathymic precursors with bone marrow stem cells. Only T lineage product cells were detected when the intrathymic precursor population was transferred back into an irradiated thymus. However, when the intrathymic precursor population was transferred intravenously, it displayed the capacity to develop into both B and T lymphoid cells in recipient bone marrow, spleen, and lymph nodes, but no donor-derived myeloid cells were detected. The absence of myeloid and erythroid precursor activity was confirmed by showing that the intrathymic precursor population was unable to develop into myeloid or erythroid spleen colonies on intravenous transfer or to form colonies in an agar culture. These findings indicate that this earliest intrathymic precursor population has become restricted (or strongly biased) to lymphoid lineage development, but not exclusively to T lymphocytes.


Asunto(s)
Células Madre Hematopoyéticas/fisiología , Linfocitos T/fisiología , Timo/citología , Agar , Animales , Antígenos de Superficie/análisis , Células de la Médula Ósea , Antígenos CD4/análisis , Ratones , Ratones Endogámicos C57BL , Rodamina 123 , Rodaminas , Antígenos Thy-1
10.
Proc Inst Mech Eng H ; 224(9): 1039-49, 2010.
Artículo en Inglés | MEDLINE | ID: mdl-21053769

RESUMEN

The aim of this study was to use a biomechanical model of the shoulder to examine the characteristics of two concepts of reverse anatomy implant; those that preserve the natural glenohumeral centre such as the Bayley-Walker (B-W) replacement and those medializing it such as Delta. A biomechanical model of the shoulder was used to evaluate the biomechanical characteristics of these prostheses. The moment arms of the shoulder muscles were predicted for the implanted models over a wide workspace and were compared to those of natural anatomy. The deltoid muscle moment arms through almost all of the range of motion in the Delta model were greatest. As a result the shoulder joint contact force was decreased for this implant. Furthermore, although the B-W model predicted similar moment arms to natural anatomy, the contact force decreased owing to change in the joint constraints. Finally, it was concluded that the reverse anatomy can compensate for loss of rotator cuff muscles in terms of joint stability, yet the shoulder function depends on the individual's musculature.


Asunto(s)
Diseño de Prótesis , Articulación del Hombro/anatomía & histología , Articulación del Hombro/cirugía , Fenómenos Biomecánicos , Ingeniería Biomédica , Humanos , Rango del Movimiento Articular , Manguito de los Rotadores/fisiopatología , Manguito de los Rotadores/cirugía , Lesiones del Manguito de los Rotadores , Articulación del Hombro/fisiología
11.
Br J Cancer ; 101(12): 2043-7, 2009 Dec 15.
Artículo en Inglés | MEDLINE | ID: mdl-19935797

RESUMEN

BACKGROUND: In a genome-wide scan (GWS) of 175 multiplex prostate cancer (PCa) families from the University of Michigan Prostate Cancer Genetics Project (PCGP), linkage was observed to markers on chromosome 17q21-24, a region that includes two breast cancer susceptibility genes, BRCA1 and BRIP1. BRIP1 is a Fanconi anaemia gene (FANCJ) that interacts with the BRCT domain of BRCA1 and has a role in DNA damage repair. Protein truncating mutations in BRIP1 have been identified in hereditary breast and ovarian cancer families, and a recent report suggested that a recurrent truncating mutation (R798X) may have a role in PCa susceptibility. METHODS: We examined the role of BRIP1 mutations in hereditary PCa through sequence analysis of 94 individuals from PCGP families showing linkage to 17q. RESULTS: A total of 24 single-nucleotide polymorphisms, including 7 missense variants but no protein truncating mutations, were observed. CONCLUSION: The data presented here suggest that BRIP1 truncating mutations are uncommon in PCa cases and do not account for the linkage to chromosome 17q observed in our GWS. Additional investigation is needed to determine the significance, if any, of the observed BRIP1 missense variants in hereditary PCa.


Asunto(s)
Cromosomas Humanos Par 17/genética , Proteínas de Unión al ADN/genética , Mutación , Neoplasias de la Próstata/genética , ARN Helicasas/genética , Anciano , Proteínas del Grupo de Complementación de la Anemia de Fanconi , Femenino , Ligamiento Genético , Humanos , Masculino , Persona de Mediana Edad , Polimorfismo de Nucleótido Simple
12.
J Cell Biol ; 77(1): 35-47, 1978 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-307001

RESUMEN

A colony-stimulating factor (M-CSF) has been partially purified and concentrated from mouse yolk sac-conditioned medium (YSCM). M-CSF appeared to preferentially stimulate CBA bone marrow granulocyte-macrophage progenitor cells (GM-CFC) to differentiate to form macrophage colonies in semisolid agar cultures. By comparison, colony-stimulating factor (GM-CSF) from mouse lung-conditioned medium (MLCM) stimulated the formation of granulocytic, mixed granulocytic-macrophage, and pure macrophage colonies. Mixing experiments indicated that both M-CSF and GM-CSF stimulated all of the GM-CFC but that the smaller CFC were more sensitive to GM-CSF and that the larger CFC were more sensitive to M-CSF. Almost all developing "clones" stimulated initially with M-CSF continued to develop when transferred to cultures containing GM-CSF. In the converse situation, only 50% of GM-CSF prestimulated "clones" survived when transferred to cultures containing M-CSF. All clones initially stimulated by M-CSF or transferred to cultures stimulated by M-CSF contained macrophages after 7 days of culture. These results suggest that there is a population of cells (GM-CFC) that are capable of differentiating to form both granulocytes and macrophages, but, once these cells are activated by a specific CSF (e.g. M-CSF), they are committed to a particular differentiation pathway. The pattern of CFC differentiation was not directly related to the rate of proliferation: cultures maximally stimulated by M-CSF produced mostly macrophage colonies, but the presence of small amounts of GM-CSF produced granulocytic cells in 30% of the colonies. Gel filtration, polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate, and affinity chromatography with concanavalin A-Sepharose indicated that M-CSF from yolk sacs was a glycoprotein with an apparent molecular weight of 60,000. There was some heterogeneity of the carbohydrate portion of the molecule as evidenced by chromatography on concanavalin A-Sepharose.


Asunto(s)
Factores Estimulantes de Colonias/farmacología , Glicoproteínas/farmacología , Macrófagos/citología , Saco Vitelino , Animales , Diferenciación Celular , Células Clonales/citología , Factores Estimulantes de Colonias/análisis , Factores Estimulantes de Colonias/aislamiento & purificación , Medios de Cultivo , Granulocitos/citología , Pulmón , Ratones , Peso Molecular
13.
J Cell Biol ; 118(3): 741-51, 1992 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-1639855

RESUMEN

Amphiregulin (AR) is a newly discovered glycosylated, 84-amino acid residue polypeptide growth regulator which has sequence homology to the EGF family of proteins. To obtain immunological reagents to study the biological role of AR, two synthetic peptides containing sequences corresponding to distinct regions of AR were used to generate polyclonal antibodies in rabbits. One preparation of antipeptide antibodies directed against residues 26-44 of AR (AR-Ab2) was most effective in the detection of native AR, whereas another preparation of antibodies against residues 8-26 (AR-Ab1) was found to be most efficacious in the detection of AR in formalin-fixed and paraffin-embedded tissues. The growth of a colon carcinoma cell line, Geo, which proliferates autonomously under serum-free conditions, was stimulated by the exogenous addition of AR or EGF. Half-maximal stimulation of this growth was observed at 40 and 200 pM of EGF and AR, respectively. A mAb to the extracellular domain of the EGF receptor blocked the stimulation of cell proliferation induced by the exogenous addition of AR, suggesting that this stimulation was mediated via the EGF receptor. Geo cells were found to constitutively express significant levels of the AR mRNA transcript as determined by analysis of the polymerase chain reaction-amplified cDNA product and AR protein was detected immunocytochemically using the AR-Ab1 antibodies in these cells. AR was immunoprecipitated specifically using the AR-Ab2 antibodies from the conditioned medium of Geo cells, which had been metabolically labeled with [35S]cysteine. The secreted AR migrated as a broad band (18.5-22.5 kD) with a median molecular weight of approximately 20.7 kD in SDS-PAGE. Immunospecific removal of AR from serum-free medium conditioned by the Geo cells and readdition of the AR-depleted medium to Geo cells resulted in an approximately 40% inhibition of cell growth relative to controls. Furthermore, the growth of the Geo cells was also inhibited by approximately 50% by the addition of the anti-EGF receptor mAb alone. These results indicate that AR and the EGF receptor are involved in the autocrine growth of these cells and suggests that AR may act through the EGF receptor via an extracellular autocrine loop. To study the expression of AR in human colon in vivo, AR was localized immunocytochemically in formalin-fixed, paraffin-embedded sections from normal and malignant human colon using the AR-Ab1 antibodies.(ABSTRACT TRUNCATED AT 400 WORDS)


Asunto(s)
Colon/metabolismo , Neoplasias del Colon/metabolismo , Glicoproteínas/fisiología , Sustancias de Crecimiento/fisiología , Péptidos y Proteínas de Señalización Intercelular , Anfirregulina , Anticuerpos Monoclonales/inmunología , División Celular/fisiología , Medios de Cultivo , Familia de Proteínas EGF , Receptores ErbB/metabolismo , Glicoproteínas/metabolismo , Sustancias de Crecimiento/metabolismo , Humanos , Inmunohistoquímica , Pruebas de Precipitina , ARN Mensajero/genética , Transcripción Genética , Células Tumorales Cultivadas
14.
J Aerosol Sci ; 40(2): 122-133, 2009 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-32287373

RESUMEN

Size distributions of expiratory droplets expelled during coughing and speaking and the velocities of the expiration air jets of healthy volunteers were measured. Droplet size was measured using the interferometric Mie imaging (IMI) technique while the particle image velocimetry (PIV) technique was used for measuring air velocity. These techniques allowed measurements in close proximity to the mouth and avoided air sampling losses. The average expiration air velocity was 11.7 m/s for coughing and 3.9 m/s for speaking. Under the experimental setting, evaporation and condensation effects had negligible impact on the measured droplet size. The geometric mean diameter of droplets from coughing was 13.5 µm and it was 16.0 µm for speaking (counting 1-100). The estimated total number of droplets expelled ranged from 947 to 2085 per cough and 112-6720 for speaking. The estimated droplet concentrations for coughing ranged from 2.4 to 5.2 cm-3 per cough and 0.004-0.223 cm-3 for speaking.

15.
J Environ Monit ; 11(11): 2087-90, 2009 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19890566

RESUMEN

Bag sampling techniques can be used to temporarily store the aerosol and therefore provide sufficient time to utilize sensitive but slow instrumental techniques for recording detailed particle size distributions. Laboratory based assessment of the method was conducted to examine size dependant deposition loss coefficients for aerosols held in Velostat bags conforming to a horizontal cylindrical geometry. Deposition losses of NaCl particles in the range of 10 nm to 160 nm were analysed in relation to the bag size, storage time, and sampling flow rate. Results of this study suggest that the bag sampling method is most useful for moderately short sampling periods of about 5 minutes.


Asunto(s)
Aerosoles/química , Monitoreo del Ambiente/instrumentación , Material Particulado/química , Material Particulado/aislamiento & purificación , Cloruro de Sodio/química , Monitoreo del Ambiente/métodos , Nanopartículas , Tamaño de la Partícula , Factores de Tiempo
16.
N Engl J Med ; 352(22): 2271-84, 2005 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-15930418

RESUMEN

BACKGROUND: The incidence and severity of herpes zoster and postherpetic neuralgia increase with age in association with a progressive decline in cell-mediated immunity to varicella-zoster virus (VZV). We tested the hypothesis that vaccination against VZV would decrease the incidence, severity, or both of herpes zoster and postherpetic neuralgia among older adults. METHODS: We enrolled 38,546 adults 60 years of age or older in a randomized, double-blind, placebo-controlled trial of an investigational live attenuated Oka/Merck VZV vaccine ("zoster vaccine"). Herpes zoster was diagnosed according to clinical and laboratory criteria. The pain and discomfort associated with herpes zoster were measured repeatedly for six months. The primary end point was the burden of illness due to herpes zoster, a measure affected by the incidence, severity, and duration of the associated pain and discomfort. The secondary end point was the incidence of postherpetic neuralgia. RESULTS: More than 95 percent of the subjects continued in the study to its completion, with a median of 3.12 years of surveillance for herpes zoster. A total of 957 confirmed cases of herpes zoster (315 among vaccine recipients and 642 among placebo recipients) and 107 cases of postherpetic neuralgia (27 among vaccine recipients and 80 among placebo recipients) were included in the efficacy analysis. The use of the zoster vaccine reduced the burden of illness due to herpes zoster by 61.1 percent (P<0.001), reduced the incidence of postherpetic neuralgia by 66.5 percent (P<0.001), and reduced the incidence of herpes zoster by 51.3 percent (P<0.001). Reactions at the injection site were more frequent among vaccine recipients but were generally mild. CONCLUSIONS: The zoster vaccine markedly reduced morbidity from herpes zoster and postherpetic neuralgia among older adults.


Asunto(s)
Vacuna contra la Varicela , Herpes Zóster/prevención & control , Herpesvirus Humano 3 , Neuralgia/prevención & control , Anciano , Vacuna contra la Varicela/efectos adversos , Vacuna contra la Varicela/inmunología , Costo de Enfermedad , Método Doble Ciego , Femenino , Estudios de Seguimiento , Herpes Zóster/complicaciones , Herpes Zóster/epidemiología , Herpesvirus Humano 3/inmunología , Humanos , Memoria Inmunológica , Incidencia , Masculino , Persona de Mediana Edad , Neuralgia/virología , Vacunas Atenuadas/efectos adversos , Vacunas Atenuadas/inmunología , Activación Viral
17.
Gait Posture ; 27(2): 177-88, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17509885

RESUMEN

Joint modelling plays an important role in qualitative and quantitative descriptions of both normal and abnormal joints, as well as predicting outcomes of alterations to joints in orthopaedic practice and research. Contemporary efforts in modelling have focussed upon the major articulations of the lower limb. Well-constrained arthrokinematics can form the basis of manageable kinetic and dynamic mathematical predictions. In order to contain computation of shoulder complex modelling, glenohumeral joint representations in both limited and complete shoulder girdle models have undergone a generic simplification. As such, glenohumeral joint models are often based upon kinematic descriptions of inadequate degrees of freedom (DOF) for clinical purposes and applications. Qualitative descriptions of glenohumeral motion range from the parody of a hinge joint to the complex realism of a spatial joint. In developing a model, a clear idea of intention is required in order to achieve a required application. Clinical applicability of a model requires both descriptive and predictive output potentials, and as such, a high level of validation is required. Without sufficient appreciation of the clinical intention of the arthrokinematic foundation to a model, error is all too easily introduced. Mathematical description of joint motion serves to quantify all relevant clinical parameters. Commonly, both the Euler angle and helical (screw) axis methods have been applied to the glenohumeral joint, although concordance between these methods and classical anatomical appreciation of joint motion is limited, resulting in miscommunication between clinician and engineer. Compounding these inconsistencies in motion quantification is gimbal lock and sequence dependency.


Asunto(s)
Rango del Movimiento Articular/fisiología , Articulación del Hombro/fisiología , Fenómenos Biomecánicos , Humanos , Matemática , Modelos Anatómicos , Rotación , Articulación del Hombro/fisiopatología
18.
Proc Inst Mech Eng H ; 222(7): 1081-95, 2008 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19024156

RESUMEN

Lines of action of muscle forces imply the function and performance of muscles acting around joints. It is not always possible to determine muscle force lines of action in vivo, and so computational techniques are often used to predict them. It is common to model a muscle as a taut elastic string that follows the shortest geodesic path between attachments over the wrapping geometry. A number of studies have been concerned with wrapping paths over single wrapping objects, and those that have considered more objects have applied the single-object solutions with iterative approaches to the search for a solution. This study presents a more efficient methodology for finding the exact solutions to a certain class of wrapping problems in which the path is constrained by multiple surfaces. It also introduces a more general wrapping technique based on the idea of energy minimization, which has been successfully validated against the exact solution. These methods are applied to the case of an element of the deltoid wrapping around the humerus modelled as a composite sphere-cylinder. Comparison of results with those obtained from approximated single-object solutions demonstrates the need to include correct multi-object wrapping algorithms in biomechanical models.


Asunto(s)
Algoritmos , Húmero/fisiología , Modelos Biológicos , Músculo Esquelético/fisiología , Articulación del Hombro/fisiología , Simulación por Computador , Humanos , Húmero/anatomía & histología , Modelos Anatómicos , Músculo Esquelético/anatomía & histología , Articulación del Hombro/anatomía & histología
19.
J Clin Invest ; 84(5): 1488-96, 1989 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-2478588

RESUMEN

Murine marrow cells infected with a retroviral vector (MPZen) bearing a granulocyte-colony-stimulating factor (G-CSF) cDNA insert were transplanted into lethally irradiated recipients to study the effects of autocrine production of G-CSF in normal hemopoietic cells. Most animals remained healthy with no evidence of tissue damage throughout the observation period (4-30 wk) despite high circulating G-CSF levels (range 2,000-26,000,000 U/ml). A dramatic neutrophilic granulocytosis was observed in all hemopoietic tissues with neutrophilic infiltration occurring in the lung and liver. Spleen, peritoneal, and peripheral blood cellularity increased approximately three-, two-, and eightfold, respectively, but total bone marrow cell counts remained unchanged. Progenitor cell numbers granulocyte-macrophage colony-forming cell (GM-CFC), granulocyte colony-forming cell (G-CFC), burst-forming unit-erythroid (BFU-E), colony-forming unit-erythroid (CFU-E) and mixed colony-forming cells (Mix-CFC) were elevated between 10-100-fold in the spleen, peritoneal cavity, and peripheral blood, but were unaffected or slightly depressed in the marrow. No tumors developed in syngeneic recipients transplanted with bone marrow or spleen cells from such mice, confirming the nonneoplastic nature of the hyperplasia induced by chronic G-CSF stimulation. These experiments also indicated the stable integration of MPZen vectors in infected cells, as evident from the continuous expression of the inserted gene for at least 6 mo, and from the ability of infected stem cells from the primary recipients to express the gene in lethally irradiated secondary recipients.


Asunto(s)
Médula Ósea/patología , Factores Estimulantes de Colonias/farmacología , Granulocitos/patología , Células Madre Hematopoyéticas/patología , Retroviridae/genética , Animales , Factores Estimulantes de Colonias/sangre , Factores Estimulantes de Colonias/genética , ADN/genética , Expresión Génica , Vectores Genéticos , Factor Estimulante de Colonias de Granulocitos , Trasplante de Células Madre Hematopoyéticas , Hiperplasia , Ratones , Ratones Endogámicos C57BL , Bazo/patología , Transfección
20.
Disabil Rehabil ; 28(15): 899-907, 2006 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-16861197

RESUMEN

BACKGROUND: The Tardieu Scale has been suggested a more appropriate clinical measure of spasticity than the Ashworth or modified Ashworth Scales. It appears to adhere more closely to Lance's definition of spasticity as it involves assessment of resistance to passive movement at both slow and fast speeds. OBJECTIVE: To review the available literature in which the Tardieu Scale has been used or discussed as a measure of spasticity, with a view to determining its validity and reliability. STUDY DESIGN: A systematic review of all literature found related to the Tardieu Scale (keywords: Tardieu scale, spasticity) from Pubmed and Ovid databases, including medline, CINAHL, EMBASE, Journals at Ovid full text, EBM reviews and Cochrane database of systematic reviews. Hand searching was also used to track the source literature. CONCLUSIONS: In theory, we can acknowledge that the Tardieu Scale does, in fact, adhere more closely to Lance's definition of spasticity. However, there is a dearth of literature investigating validity and reliability of the scale. Some studies have identified the Tardieu Scale to be more sensitive than other measures, to change following treatment with botulinum toxin. Further studies need to be undertaken to clarify the validity and reliability of the scale for a variety of muscle groups in adult neurological patients.


Asunto(s)
Evaluación de la Discapacidad , Espasticidad Muscular/clasificación , Humanos , Movimiento , Valores de Referencia , Reproducibilidad de los Resultados , Índice de Severidad de la Enfermedad
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