Search results for "physiologic"

Molecular mechanisms of endomembrane trafficking in plants

2021

Abstract Endomembrane trafficking is essential for all eukaryotic cells. The best-characterized membrane trafficking organelles include the endoplasmic reticulum (ER), Golgi apparatus, early and recycling endosomes, multivesicular body, or late endosome, lysosome/vacuole, and plasma membrane. Although historically plants have given rise to cell biology, our understanding of membrane trafficking has mainly been shaped by the much more studied mammalian and yeast models. Whereas organelles and major protein families that regulate endomembrane trafficking are largely conserved across all eukaryotes, exciting variations are emerging from advances in plant cell biology research. In this review, …

Putrescine accumulation in Arabidopsis thaliana transgenic lines enhances tolerance to dehydration and freezing stress

2011

Polyamines have been globally associated to plant responses to abiotic stress. Particularly, putrescine has been related to a better response to cold and dehydration stresses. It is known that this polyamine is involved in cold tolerance, since Arabidopsis thaliana plants mutated in the key enzyme responsible for putrescine synthesis (arginine decarboxilase, ADC; EC 4.1.1.19) are more sensitive than the wild type to this stress. Although it is speculated that the over-expression of ADC genes may confer tolerance, this is hampered by pleiotropic effects arising from the constitutive expression of enzymes from the polyamine metabolism. Here, we present our work using A. thaliana transgenic pl…

Acoustic monitoring of the artificial airway — experimental results

1997

Non-invasive acoustic airway-monitoring was evaluated in an experimental study. Recording amplitude and travel time of acoustic pulse response, an acoustic pattern of airway's geometry was then calculated. Measurements on models and excised human cadaver lungs were performed to discover whether displacement or obstruction of the artificial airway could be detected by its acoustic equivalent. Regression analysis revealed a close correlation between displacement of tracheostomy tubes and the shifting of the acoustic area-distance function (corr. coeff.: 0.97-1) and an adequate correlation between acoustic and planimetrical determination of cross-sectional area within the tubes (corr. coeff.: …

Isoquercitrin and polyphosphate co-enhance mineralization of human osteoblast-like SaOS-2 cells via separate activation of two RUNX2 cofactors AFT6 a…

2014

Isoquercitrin, a dietary phytoestrogen, is a potential stimulator of bone mineralization used for prophylaxis of osteoporotic disorders. Here we studied the combined effects of isoquercitrin, a cell membrane permeable 3-O-glucoside of quercetin, and polyphosphate [polyP], a naturally occurring inorganic polymer inducing bone formation, on mineralization of human osteoblast-like SaOS-2 cells. Both compounds isoquercitrin and polyP induce at non-toxic concentrations the mineralization process of SaOS-2 cells. Co-incubation experiments revealed that isoquercitrin (at 0.1 and 0.3μM), if given simultaneously with polyP (as Ca(2+) salt; at 3, 10, 30 and 100μM) amplifies the mineralization-enhanci…

Psychological State after an Acute Coronary Syndrome: Impact of Physical Limitations

2021

The aim of this study was to investigate how physical limitations after ACS influence patients’ quality of life and health perception. This was a longitudinal clinical study. We recruited 146 patients diagnosed with ACS. The patients performed a stress test (Bruce’s protocol) for the evaluation of physical limitations and were classified according to the test result: without physical limitations (more than 10 METS), with some physical limitations (7 to 9 METS), and with high physical limitations (less than 6 METS). Significant differences were found between the three groups immediately after the diagnosis of ACS and after a period of three months, regarding health perception, anxiety, depre…

Acute stress and working memory in older people.

2015

Several studies have shown that acute stress affects working memory (WM) in young adults, but the effect in older people is understudied. As observed in other types of memory, older people may be less sensitive to acute effects of stress on WM. We performed two independent studies with healthy older men and women (from 55 to 77 years old) to investigate the effects of acute stress (Trier Social Stress Test; TSST) and cortisol on WM. In study 1 (n = 63), after the TSST women (but not men) improved their performance on Digit Span Forward (a measure of the memory span component of WM) but not on Digit Span Backward (a measure of both memory span and the executive component of WM). Furthermore,…

2016

The flexible access to information in working memory is crucial for adaptive behavior. It is assumed that this is realized by switching the focus of attention within working memory. Switching of attention is mirrored in the P3a component of the human event-related brain potential (ERP) and it has been argued that the processes reflected by the P3a are also relevant for selecting information within working memory. The aim of the present study was to further evaluate whether the P3a mirrors genuine switching of attention within working memory by applying an object switching task: Participants updated a memory list of four digits either by replacing one item with another digit or by processing…

2013

Distraction of goal-oriented performance by a sudden change in the auditory environment is an everyday life experience. Different types of changes can be distracting, including a sudden onset of a transient sound and a slight deviation of otherwise regular auditory background stimulation. With regard to deviance detection, it is assumed that slight changes in a continuous sequence of auditory stimuli are detected by a predictive coding mechanisms and it has been demonstrated that this mechanism is capable of distracting ongoing task performance. In contrast, it is open whether transient detection – which does not rely on predictive coding mechanisms – can trigger behavioral distraction, too…

Does predation maintain eyespot plasticity in Bicyclus anynana?

2004

The butterfly Bicyclus anynana exhibits phenotypic plasticity involving the wet-season phenotype, which possesses marginal eyespots on the ventral surface of the wings, and the dry-season form, which lacks these eyespots. We examined the adaptive value of phenotypic plasticity of B. anynana in relation to the defence mechanisms of crypsis and deflection. We assessed the visibility differences between spotless and spotted butterflies against backgrounds of brown (dry season) or green (wet season) leaves. Spotless butterflies were highly cryptic and less predated by adult bird predators than were spotted ones when presented against brown leaf litter. However, the advantage of crypsis disappea…

Standardized long-term follow-up after endoscopic resection of large, nonpedunculated colorectal lesions: a prospective two-center study.

2014

Endoscopic removal of large, nonpedunculated colorectal lesions is challenging. Long-term outcome data based on standardized protocols, including detailed inspection of the resection site, are scarce. The aims of the present study were to evaluate the safety and efficacy of endoscopic resection (ER) of large, nonpedunculated lesions (LNLs;20 mm) and to assess the long-term recurrence rate afterward.A total of 243 consecutive patients (141 men, 102 women) with 252 adenomas (20 mm) was followed up using a standardized protocol after complete ER. After endoscopic treatment, the patients received standardized follow-up examinations after 3-6 months and 12 months. The postpolypectomy scar was re…