614 research outputs found
Flow patterns generated by oblate medusan jellyfish: field measurements and laboratory analyses
Flow patterns generated by medusan swimmers such as
jellyfish are known to differ according the morphology of
the various animal species. Oblate medusae have been
previously observed to generate vortex ring structures
during the propulsive cycle. Owing to the inherent
physical coupling between locomotor and feeding
structures in these animals, the dynamics of vortex ring
formation must be robustly tuned to facilitate effective
functioning of both systems. To understand how this is
achieved, we employed dye visualization techniques on
scyphomedusae (Aurelia aurita) observed swimming in
their natural marine habitat. The flow created during each
propulsive cycle consists of a toroidal starting vortex
formed during the power swimming stroke, followed by a
stopping vortex of opposite rotational sense generated
during the recovery stroke. These two vortices merge in a
laterally oriented vortex superstructure that induces flow
both toward the subumbrellar feeding surfaces and
downstream. The lateral vortex motif discovered here
appears to be critical to the dual function of the medusa
bell as a flow source for feeding and propulsion.
Furthermore, vortices in the animal wake have a greater
volume and closer spacing than predicted by prevailing
models of medusan swimming. These effects are shown to
be advantageous for feeding and swimming performance,
and are an important consequence of vortex interactions
that have been previously neglected
Kidney disease in lupus is not always 'lupus nephritis'
In lupus erythematosus, elevated serum creatinine levels and urinary abnormalities implicate a kidney disorder, which may not always be lupus nephritis as defined by the current classification of the International Society of Nephrology/Renal Pathology Society. The signs of renal dysfunction may be caused by lupusunrelated renal injury such as drug toxicity or infection or by lupus-associated mechanisms that are not part of the classification, such as minimal change nephrotic syndrome or thrombotic microangiopathy. The latter seems to complicate lupus nephritis more frequently than previously thought. An unbiased assessment of kidney disease in lupus requires a kidney (re-)biopsy to define the appropriate management
Evaluation of an Oral Care Program to Improve the Oral Health of Home-Dwelling Older People
The aim of this study was to evaluate the impact of the implementation of an Oral Care Program on home care nurses' attitudes and knowledge about oral health (care) and the impact on older people's oral health. A pre-post study, without a control group, was conducted. A preventive Oral Care Program (OCP) was designed, focusing on home care nurses and older people, in collaboration with dental hygienists. Implementation was measured with questionnaires at baseline and after 6 months for home care nurses; for older people, implementation was measured at baseline and after 3 months with the Oral Health Assessment Tool and a questionnaire about oral (self) care between January 2018 and September 2019. Although the study design has limitations, the oral health of older people improved significantly after 3 months and the OCP was most beneficial for people with full dentures. The OCP improved knowledge and attitude of home care nurses. The program fitted well with the daily work routines of home care nurses. Individual-centered care plans for older people, education of home care nurses and the expertise of the dental hygienists have added value in home care nursing. Future implementations should focus on older people with natural teeth
Kidney failure in mice lacking the tetraspanin CD151
The tetraspanin CD151 is a cell-surface molecule known for its strong lateral interaction with the laminin-binding integrin α3ÎČ1. Patients with a nonsense mutation in CD151 display end-stage kidney failure associated with regional skin blistering and sensorineural deafness, and mice lacking the integrin α3 subunit die neonatally because of severe abnormalities in the lung and kidney epithelia. We report the generation of Cd151-null mice that recapitulate the renal pathology of human patients, i.e., with age they develop massive proteinuria caused by focal glomerulosclerosis, disorganization of the glomerular basement membrane, and tubular cystic dilation. However, neither skin integrity nor hearing ability are impaired in the Cd151-null mice. Furthermore, we generated podocyte-specific conditional knockout mice for the integrin α3 subunit that show renal defects similar to those in the Cd151 knockout mice. Our results support the hypothesis that CD151 plays a key role in strengthening α3ÎČ1-mediated adhesion in podocytes
Overexpression of Mcl-1 exacerbates lymphocyte accumulation and autoimmune kidney disease in lpr mice
Cell death by apoptosis has a critical role during embryonic development and in maintaining tissue homeostasis. In mammals,
there are two converging apoptosis pathways: the âextrinsicâ pathway, which is triggered by engagement of cell surface âdeath
receptorsâ such as Fas/APO-1; and the âintrinsicâ pathway, which is triggered by diverse cellular stresses, and is regulated by prosurvival
and pro-apoptotic members of the Bcl-2 family of proteins. Pro-survival Mcl-1, which can block activation of the proapoptotic
proteins, Bax and Bak, appears critical for the survival and maintenance of multiple haemopoietic cell types. To
investigate the impact on haemopoiesis of simultaneously inhibiting both apoptosis pathways, we introduced the vavP-Mcl-1
transgene, which causes overexpression of Mcl-1 protein in all haemopoietic lineages, into Faslpr/lpr mice, which lack functional
Fas and are prone to autoimmunity. The combined mutations had a modest impact on myelopoiesis, primarily an increase in the
macrophage/monocyte population in Mcl-1tg/lpr mice compared with lpr or Mcl-1tg mice. The impact on lymphopoiesis was
striking, with a marked elevation in all major lymphoid subsets, including the non-conventional double-negative (DN) T cells
(TCRÎČ+
CD4â
CD8â
B220+
) characteristic of Faslpr/lpr mice. Of note, the onset of autoimmunity was markedly accelerated in Mcl-1tg/lpr
mice compared with lpr mice, and this was preceded by an increase in immunoglobulin (Ig)-producing cells and circulating
autoantibodies. This degree of impact was surprising, given the relatively mild phenotype conferred by the vavP-Mcl-1 transgene
by itself: a two- to threefold elevation of peripheral B and T cells, no significant increase in the non-conventional DN T-cell
population and no autoimmune disease. Comparison of the phenotype with that of other susceptible mice suggests that the
development of autoimmune disease in Mcl-1tg/lpr mice may be influenced not only by Ig-producing cells but also other
haemopoietic cell types
Renal transplantation for lupus nephritis: non-adherence and graft survival
Objectives: Poor adherence to immunosuppressive treatment is common in patients with systemic lupus erythematosus and may identify those with lupus nephritis (LN) who have a poorer prognosis. Non-adherence has also been reported to be a potential adverse outcome predictor in renal transplantation (rTp). We investigated whether non-adherence is associated with increased rTp graft rejection and/or failure in patients with LN. Methods: Patients with LN undergoing rTp in two major London hospitals were retrospectively included. Medical and electronic records were reviewed for documented concerns of non-adherence as well as laboratory biochemical drug levels. The role of non-adherence and other potential predictors of graft rejection/failure including demographics, comorbidities, age at systemic lupus erythematosus and LN diagnosis, type of LN, time on dialysis prior to rTp and medication use were investigated using logistic regression. Results: Out of 361 patients with LN, 40 had rTp. During a median follow-up of 8.7 years, 17/40 (42.5%) of these patients had evidence of non-adherence. A total of 12 (30.0%) patients experienced graft rejection or failure or both. In the adherent group 2/23 (8.7%) had graft rejection, whilst in the non-adherent this rose to 5/17 (29.4%, pâ=â0.11). Graft failure was seen in 5/23 (21.7%) patients from the adherent group and 4/17 (23.5%) in the non-adherent group (pâ=â0.89). Non-adherent patients had a trend towards increased graft rejection, hazard ratio 4.38, 95% confidence intervalâ=â0.73â26.12, pâ=â0.11. Patients who spent more time on dialysis prior to rTp were more likely to be adherent to medication, pâ=â0.01. Conclusion: Poor adherence to immunosuppressive therapy is common and has been shown to associate with a trend towards increased graft failure in patients with LN requiring rTp. This is the first paper to report that shorter periods on dialysis prior to transplantation might lead to increased non-adherence in lupus patients
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