RESUMEN
As the recovery from gait perturbations is coordinatively complex and error-prone, people often adopt anticipatory strategies when the perturbation is expected. These anticipatory strategies act as a first line of defence against potential balance loss. Since age-related changes in the sensory and neuromotor systems could make the recovery from external perturbations more difficult, it is important to understand how older adults implement anticipatory strategies. Therefore, we exposed healthy young (N = 10, 22 ± 1.05 yrs.) and older adults (N = 10, 64.2 ± 6.07 yrs.) to simulated slips on a treadmill with consistent properties and assessed if the reliance on anticipatory control differed between groups. Results showed that for the unperturbed steps in between perturbations, step length decreased and the backward (BW) margin of stability (MOS) increased (i.e., enhanced dynamic stability against backward loss of balance) in the leg that triggered the slip, while step lengths increased and BW MOS decreased in the contralateral leg. This induced step length and BW MOS asymmetry was significantly larger for older adults. When exposed to a series of predictable slips, healthy older adults thus rely more heavily on anticipatory control to proactively accommodate the expected backward loss of balance.
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Accidentes por Caídas , Envejecimiento , Caminata , Humanos , Masculino , Adulto Joven , Persona de Mediana Edad , Anciano , Accidentes por Caídas/prevención & control , Pierna/fisiología , Antropometría , Caminata/fisiología , Envejecimiento/fisiologíaRESUMEN
The Southern Ocean greatly contributes to the regulation of the global climate by controlling important heat and carbon exchanges between the atmosphere and the ocean. Rates of climate change on decadal timescales are therefore impacted by oceanic processes taking place in the Southern Ocean, yet too little is known about these processes. Limitations come both from the lack of observations in this extreme environment and its inherent sensitivity to intermittent processes at scales that are not well captured in current Earth system models. The Southern Ocean Carbon and Heat Impact on Climate programme was launched to address this knowledge gap, with the overall objective to understand and quantify variability of heat and carbon budgets in the Southern Ocean through an investigation of the key physical processes controlling exchanges between the atmosphere, ocean and sea ice using a combination of observational and modelling approaches. Here, we provide a brief overview of the programme, as well as a summary of some of the scientific progress achieved during its first half. Advances range from new evidence of the importance of specific processes in Southern Ocean ventilation rate (e.g. storm-induced turbulence, sea-ice meltwater fronts, wind-induced gyre circulation, dense shelf water formation and abyssal mixing) to refined descriptions of the physical changes currently ongoing in the Southern Ocean and of their link with global climate. This article is part of a discussion meeting issue 'Heat and carbon uptake in the Southern Ocean: the state of the art and future priorities'.
RESUMEN
The ability to flexibly respond and adapt the walking pattern over time to unexpected gait perturbations is pivotal for safe and efficient locomotion. However, these abilities might be affected by age due to age-related changes in sensorimotor functioning. In this cross-sectional lifespan study, we used a split-belt paradigm to determine how age affects the initial response (i.e., flexibility)-and the ability to adapt after prolonged exposure-to a sustained gait perturbation. Healthy adults (N = 75) of different ages (12-13 per decade) were included and walked on a split-belt treadmill, in which a sustained gait perturbation was imposed by increasing one of the belt speeds. Linear regression models, with the evoked spatiotemporal gait asymmetry during the early perturbation and late adaptation, were performed to determine the effects of age on the flexibility and adaptability to split-belt walking. Results showed that the flexibility to respond to an unexpected perturbation decreased across the lifespan, as evidenced by a greater step length asymmetry (SLA) during the early perturbation phase. Despite this reduced flexibility in step lengths, late adaptation levels in SLA were comparable across different ages. With increasing age, however, subjects needed more steps to reach a stable level in SLA. Finally, when the belts were set to symmetrical speeds again, the magnitude of SLA (i.e., the aftereffects) increased with age. Collectively, these findings suggest that natural ageing comes with a decrease in gait flexibility, while the ability to adapt to split-belt walking was not affected by age-only how adaptation was achieved.
RESUMEN
BACKGROUND: Clinical nursing practice may involve moral distress, which has been reported to occur frequently when nurses care for dying patients. Palliative sedation is a practice that is used to alleviate unbearable and refractory suffering in the last phase of life and has been linked to distress in nurses. AIM: The aim of this study was to explore nurses' reports on the practice of palliative sedation focusing on their experiences with pressure, dilemmas and morally distressing situations. METHODS: In-depth interviews with 36 nurses working in hospital, nursing home or primary care. RESULTS: Several nurses described situations in which they felt that administration of palliative sedation was in the patient's best interest, but where they were constrained from taking action. Nurses also reported on situations where they experienced pressure to be actively involved in the provision of palliative sedation, while they felt this was not in the patient's best interest. The latter situation related to (1) starting palliative sedation when the nurse felt not all options to relieve suffering had been explored yet; (2) family requesting an increase of the sedation level where the nurse felt that this may involve unjustified hastening of death; (3) a decision by the physician to start palliative sedation where the patient had previously expressed an explicit wish for euthanasia. CONCLUSIONS: Nurses experienced moral distress in situations where they were not able to act in what they believed is the patient's best interest. Situations involving moral distress require nurses to be well informed and able to adequately communicate with suffering patients, distressed family and physicians.
Asunto(s)
Enfermería de Cuidados Paliativos al Final de la Vida/ética , Enfermería de Cuidados Paliativos al Final de la Vida/métodos , Hipnóticos y Sedantes/administración & dosificación , Principios Morales , Personal de Enfermería en Hospital/psicología , Dolor/tratamiento farmacológico , Adulto , Femenino , Humanos , Masculino , Persona de Mediana Edad , Investigación Cualitativa , Estrés Psicológico , Encuestas y CuestionariosRESUMEN
Up to thirty years ago, in the Netherlands the word 'stervensbegeleiding' [literally, dying-guidance] was used to refer to care for people in the last days of life. After Cicely Saunders had developed a multidisciplinary and multidimensional approach for care for the dying, the wording changed, until the word 'palliative care' was adopted. This care gradually developed from care for the dying to care for all people with life-threatening illness, as illustrated in the WHO definition. This shift in focus of care raises the question of when palliative care starts. The surprise question is regarded as a useful tool for marking this shift in focus of care. However, answering the surprise question does not inform us about palliative care needs. Nevertheless, when people enter the dying phase, a fundamental change in the nature of care is needed. The word 'stervensbegeleiding' marks this change of care.
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Comunicación , Cuidados Paliativos , Relaciones Médico-Paciente , Cuidado Terminal , Humanos , Lenguaje , Medicina , Países BajosRESUMEN
Palliative sedation is given to relieve refractory discomfort (pain, shortness of breath, agitation) during the phase when life expectancy is estimated to be a week or less. It is a medical intervention which, although not expressly meant to shorten life, may well do so. There is an inherent uncertainty here which is the cause of considerable ethical unease. Figures show that in a limited number of cases palliative sedation is actually applied with the intention to hasten death. It may well be impossible to rid ourselves ofthis uncertainty conclusively.
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Ética Médica , Hipnóticos y Sedantes , Cuidados Paliativos/métodos , Cuidado Terminal/métodos , Toma de Decisiones , Eutanasia Activa , Humanos , Países Bajos , Cuidados Paliativos/ética , Cuidado Terminal/éticaRESUMEN
Citrus waste supplemented with calcium hydroxide and with a C/N ratio of 24:1, pH of 6.3 and moisture content of 60% was composted by piling under shelter. With regular turning over of the pile and replenishment of moisture, the thermic phase lasted for 65-70 days and composting was completed after 3 months. Compost thus prepared had an air-filled porosity of 14%, water-holding capacity of 590 ml l(-1), bulk density of 1.05 g cm(-3) and conductivity of 480 mS m(-1). Phosphorus content (in mg l(-1)) was 15, potassium 1,170, calcium 362, magnesium 121, sodium 32, chloride 143, boron 0.31, and water-soluble nitrogen and organic matter 126 and 4788, respectively. Total carbon amounted to 8.85% and total nitrogen to 1.26% of the dry weight, giving a C/N ratio of 7. Mature compost showed some, but acceptable, levels of phytotoxicity. Raw citrus waste was predominantly colonised by mesophilic yeasts. Thermophilous microorganisms present during the thermic phase mainly comprised the bacterial species Bacillus licheniformis, B. macerans and B. stearothermophilus and, to a lesser extent, fungi such as Absidia corymbifera, Aspergillus fumigatus, Emericella nidulans, Penicillium diversum, Paecilomyces variotii, Rhizomucor pusillus, Talaromyces thermophilus and Thermomyces lanuginosus. Bacteria prevalent in the final product included B. licheniformis, B. macerans, Proteus vulgaris, Pseudomonas aeruginosa, P. fluorescens, P. luteola and Serratia marcescens, whereas fungi isolated most frequently comprised Aspergillus puniceus, A. ustus, E. nidulans. Paecilomyces lilacinus, T lanuginosus, yeasts and a basidiomycetous species, probably Coprinus lagopus.
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Citrus , Residuos Industriales , Hidróxido de Calcio , Hongos/metabolismo , Concentración de Iones de Hidrógeno , Eliminación de Residuos Sanitarios/métodos , Factores de TiempoRESUMEN
Nearly 10% of the world's population lives in sub-Saharan Africa, a region comprised of many countries with least developed nation status. The region has a predominantly young population and many children in the region are at risk of pathologies associated with hearing loss. Despite the constraints associated with low socioeconomic levels, a number of valuable studies have been carried out into the prevalence and etiology of childhood hearing loss in the sub-Saharan region. A review of the published literature related to childhood hearing loss in sub-Saharan Africa is presented and recommendations made on possible future research directions that could assist hearing loss prevention and management.
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Países en Desarrollo , Trastornos de la Audición/epidemiología , Trastornos de la Audición/prevención & control , Adolescente , África del Sur del Sahara/epidemiología , Distribución por Edad , Niño , Preescolar , Recolección de Datos , Femenino , Trastornos de la Audición/fisiopatología , Humanos , Masculino , Prevalencia , Factores de Riesgo , Distribución por Sexo , Factores SocioeconómicosRESUMEN
OBJECTIVES: This study examined the congruence between pediatric occupational therapists' self-care interventions and occupational therapy's philosophical base, which focuses on performance of self-care skills as primary in evaluation and intervention. METHOD: A questionnaire was mailed to 252 therapists serving children ages birth to 6 years. The questionnaire asked for therapists' perceptions about the importance, uniqueness, and frequency of 10 areas of intervention, including self-care. RESULTS: Perceived importance of self-care was found to be strongly related to perceived frequency of self-care intervention. Practice setting was significantly associated with perceptions of uniqueness of self-care, and team membership status was significantly associated with importance of self-care. Most respondents perceived self-care intervention to be important (86%) and unique (80%) to occupational therapy. Seventy percent regularly provided intervention for self-care. CONCLUSIONS: The therapists' perceptions reflected continued regard for self-care as an important and unique area of pediatric occupational therapy but were somewhat discrepant with the actual frequency of self-care interventions.
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Actitud del Personal de Salud , Autocuidado , Actividades Cotidianas , Niño , Preescolar , Femenino , Humanos , Lactante , Recién Nacido , Masculino , Resultado del TratamientoRESUMEN
A representative sample of Grade 1 (first year school entry) schoolchildren in Swaziland were surveyed during a single week to determine the prevalence of ear and hearing disorders: 79.8% had both normal ears and normal hearing, 16.8% had an ear disorder, but 80% of them had normal hearing. The most common disorder was impacted wax, with a prevalence rate of 74/1000. Middle ear disorders were common and the prevalence rate for children with active middle ear disease was 30/1000 (17/1000 having a hearing loss), and for children with inactive ear disease, the prevalence was 21/1000 (5/1000 having a hearing loss); 8/1000 children were found to have a sensorineural hearing loss, 5.3/1000 unilateral and 2.1/1000 bilateral. Improved treatment of acute otitis media, which is also common in the pre-school age group, could reduce the sequelae of the disorder, which has a deleterious effect on hearing and impairs educational achievement once the children enrol at school.
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Trastornos de la Audición/epidemiología , Trastornos de la Audición/prevención & control , Otitis Media/epidemiología , Otitis Media/prevención & control , Pruebas de Impedancia Acústica , Adolescente , Audiometría , Niño , Preescolar , Esuatini/epidemiología , Femenino , Humanos , Masculino , Tamizaje Masivo , Vigilancia de la Población , Prevalencia , Instituciones AcadémicasRESUMEN
Cyclic beta-1,2-glucan is considered to play a role in osmoadaptation of members of the family Rhizobiaceae in hypotonic media. Agrobacterium tumefaciens chvB mutants, lacking beta-1,2-glucan, exhibit a pleiotropic phenotype, including nonmotility, attachment deficiency, and avirulence. Here we report that by growth of chvB mutant cells in tryptone-yeast extract medium supplemented with 7 mM CaCl2 and 100 mM NaCl, the mutant cells become motile, attach to pea root hair tips, and are virulent on Kalanchoë leaves. Moreover, whereas chvB mutants grown in tryptone-yeast extract medium containing 7 mM CaCl2 do not produce active rhicadhesin, addition of 100 mM NaCl to this medium resulted in restoration of rhicadhesin activity. The presence of CaCl2 appeared to be required for attachment, virulence, and activity of rhicadhesin. The results support a role for cyclic beta-1,2-glucan in osmoadaptation and strengthen the notion that rhicadhesin is required for attachment and virulence of A. tumefaciens.
Asunto(s)
Agrobacterium tumefaciens/fisiología , Adhesión Bacteriana/genética , Proteínas Bacterianas/metabolismo , Plantas/microbiología , beta-Glucanos , Adaptación Biológica , Agrobacterium tumefaciens/patogenicidad , Glucanos/metabolismo , Presión Osmótica , Virulencia/genéticaRESUMEN
Attachment of Rhizobium and Agrobacterium bacteria to cells of their host plants is a two-step process. The first step, direct attachment of bacteria to the plant cell wall, is mediated by the bacterial protein rhicadhesin. A putative plant receptor molecule for rhicadhesin was purified from cell walls of pea roots using a bioassay based on suppression of rhicadhesin activity. This molecule appeared to be sensitive to treatments with pronase or glycosidase. Its isoelectric point is 6.4, and its apparent molecular mass was estimated to be 32 kDa before and 29 kDa after glycosidase treatment, as determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and ultrafiltration. The sequence of the first 29 N-terminal amino acids was determined: A-D-A-D-A-L-Q-D-L-C(?)-V-A-D-Y-A-S-V-I-L- V-N-G-F-A-S-K(Q)-(P/Q)-(L)-(I). No homology with known proteins was found. In the course of this research project the extracellular matrix protein vitronectin was reported to inhibit attachment of A. tumefaciens to carrot cells [29]. A variety of adhesive proteins, including vitronectin, contain a common cell attachment determinant with the sequence R-G-D. Since we could not detect other cell wall components able to suppress rhicadhesin activity, and since an R-G-D containing hexapeptide was also active as a receptor, we speculate that the plant receptor for rhicadhesin is a glycoprotein containing an R-G-D attachment site.
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Proteínas Bacterianas/metabolismo , Fabaceae/química , Glicoproteínas/aislamiento & purificación , Proteínas de Plantas/aislamiento & purificación , Plantas Medicinales , Secuencia de Aminoácidos , Aminoácidos/análisis , Adhesión Bacteriana , Electroforesis en Gel de Poliacrilamida , Fabaceae/metabolismo , Glicoproteínas/química , Glicoproteínas/metabolismo , Glicosilación , Punto Isoeléctrico , Datos de Secuencia Molecular , Oligopéptidos/metabolismo , Proteínas de Plantas/química , Proteínas de Plantas/metabolismo , RhizobiaceaeRESUMEN
In contrast to wild-type Agrobacterium tumefaciens strains, beta-1,2-glucan-deficient chvB mutants were found to be unable to attach to pea root hair tips. The mutants appeared to produce rhicadhesin, the protein that mediates the first step in attachment of Rhizobiaceae cells to plant root hairs, but the protein was inactive. Both attachment to root hairs and virulence of the chvB mutants could be restored by treatment of the plants with active rhicadhesin, whereas treatment of plants with beta-1,2-glucan had no effect on attachment or virulence. Moreover, nodulation ability of a chvB mutant carrying a Sym plasmid could be restored by pretreatment of the host plant with rhicadhesin. Apparently the attachment-minus and avirulence phenotype of chvB mutants is caused by lack of active rhicadhesin, rather than directly being caused by a deficiency in beta-1,2-glucan synthesis. The results strongly suggest that rhicadhesin is essential for attachment and virulence of A. tumefaciens cells. They also indicate that the mechanisms of binding of Agrobacterium and Rhizobium bacteria to plant target cells are similar, despite differences between these target cells.
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Adhesinas Bacterianas , Agrobacterium tumefaciens/fisiología , Adhesión Bacteriana/genética , Proteínas Bacterianas/genética , Proteínas Bacterianas/farmacología , Proteínas de Unión al ADN , Proteínas de la Membrana , Rhizobium/fisiología , Simbiosis/genética , Factores de Virulencia , beta-Glucanos , Agrobacterium tumefaciens/efectos de los fármacos , Agrobacterium tumefaciens/genética , Agrobacterium tumefaciens/patogenicidad , Proteínas Bacterianas/fisiología , Glucanos/metabolismo , Plantas/microbiología , Rhizobium/genética , Especificidad de la Especie , Virulencia/genéticaRESUMEN
Attachment of bacteria to plant cells is one of the earliest steps in many plant-bacterium interactions. This review covers the current knowledge on one of the best-studied examples of bacterium-plant attachment, namely the molecular mechanism by which Rhizobium bacteria adhere to plant roots. Despite differences in several studies with regard to growth conditions of bacteria and plants and to methods used for measuring attachment, an overall consensus can be drawn from the available data. Rhizobial attachment to plant root hairs appears to be a two-step process. A bacterial Ca(2+)-binding protein, designated as rhicadhesin, is involved in direct attachment of bacteria to the surface of the root hair cell. Besides this step, there is another step which results mainly in accumulation and anchoring of the bacteria to the surface of the root hair. This leads to so-called firm attachment. Depending on the growth conditions of the bacteria, the latter step is mediated by plant lectins and/or by bacterial appendages such as cellulose fibrils and fimbriae. The possible role of these adhesions in root nodule formation is discussed.
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Adhesión Bacteriana/fisiología , Fabaceae/microbiología , Plantas Medicinales , Rhizobium/fisiología , Simbiosis/fisiologíaRESUMEN
Lymphocyte and macrophage/dendritic cell populations in the oral cavity of the rat were studied by immunohistochemistry. Furthermore, the reactivity of the oral mucosa towards antigen and its position in the mucosal immune system was investigated by staining antibody-forming cells and comparing serum and saliva antibody titres. Although numerous lymphocytes and non-lymphoid cells were present in the oral mucosa, organized lymphoid tissue could not be found. The majority of the lymphocytes are T cells, particularly of the T-helper phenotype. Macrophages were found only in the connective tissue, whereas dendritic cells also occurred in the epithelium. The possible functions of the cells in the different sites of the oral mucosa are discussed. Antibody-forming cells were mainly detected in the draining superficial and posterior cervical lymph nodes and in the submandibular glands. The roles of the various compartments of the oral mucosal immune system are discussed with particular reference to the epithelium and connective tissue as induction sites, the draining lymph nodes as sites of proliferation and differentiation, and the submandibular glands as effector sites.
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Tejido Linfoide/citología , Tejido Linfoide/inmunología , Mucosa Bucal/citología , Animales , Anticuerpos/sangre , Antígenos/inmunología , Células Dendríticas/inmunología , Haptenos , Hemocianinas/inmunología , Inmunohistoquímica , Recuento de Leucocitos , Ganglios Linfáticos , Linfocitos/inmunología , Macrófagos/inmunología , Masculino , Mucosa Bucal/inmunología , Cuello , Ratas , Ratas Endogámicas , Saliva/citología , Saliva/inmunologíaRESUMEN
Nasal secretions from patients with an IgE-mediated rhinopathy, patients with a non-IgE-mediated rhinopathy, and healthy control subjects were collected with a newly developed direct aspiration system. Total protein, albumin, secretory IgA (sIgA), IgE, IgG, and IgM concentrations were measured in the nasal secretions to detect whether the nasal pathology is reflected in nasal secretion protein concentrations. It was found that protein and immunoglobulin concentrations in nasal secretions were inversely related to amount of secretion in the nasal cavity. Both patients' groups had a significantly higher sIgA to protein ratio than the healthy control subjects. Furthermore, patients with an IgE-mediated rhinopathy had significantly higher sIgA and IgM to total protein ratios in their nasal secretions than patients with a non-IgE-mediated rhinopathy. Probably these differences are due to changes in immunoregulation.
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Inmunoglobulina E/inmunología , Inmunoglobulinas/análisis , Mucosa Nasal/inmunología , Rinitis/inmunología , Adolescente , Adulto , Albúminas/análisis , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Masculino , Persona de Mediana Edad , Mucosa Nasal/metabolismo , Rinitis Alérgica Perenne/inmunología , Componente Secretorio/análisisRESUMEN
This study was designed, first, to test a new system for aspiration of human nasal secretions and, secondly, to evaluate protein and immunoglobulin concentrations in these secretions at different levels of secretory activity. The direct aspiration system combines the advantages of minimal irritation of the nasal mucosa with the facility to determine concentrations per gram of secretion. The total protein and immunoglobulin concentrations were inversely related to the amount of secretion obtained. Variations in fluid secretion throughout the day may be responsible for this relationship. The inverse relationship was much more significant in patients with nasal polyps, in which much higher concentrations were found, than in healthy subjects. Ratios of immunoglobulin to total protein were independent of the amount of secretion obtained. Compared to the controls, the ratios of IgM and IgG to protein in the secretions of the patients were significantly increased. The secretory immunoglobulin A to total protein ratios were only slightly higher in the patients' secretions.