Hasil untuk "Physiology"

G. Carta, E. Murru, S. Banni et al.

Palmitic acid (PA) has been for long time negatively depicted for its putative detrimental health effects, shadowing its multiple crucial physiological activities. PA is the most common saturated fatty acid accounting for 20–30% of total fatty acids in the human body and can be provided in the diet or synthesized endogenously via de novo lipogenesis (DNL). PA tissue content seems to be controlled around a well-defined concentration, and changes in its intake do not influence significantly its tissue concentration because the exogenous source is counterbalanced by PA endogenous biosynthesis. Particular physiopathological conditions and nutritional factors may strongly induce DNL, resulting in increased tissue content of PA and disrupted homeostatic control of its tissue concentration. The tight homeostatic control of PA tissue concentration is likely related to its fundamental physiological role to guarantee membrane physical properties but also to consent protein palmitoylation, palmitoylethanolamide (PEA) biosynthesis, and in the lung an efficient surfactant activity. In order to maintain membrane phospholipids (PL) balance may be crucial an optimal intake of PA in a certain ratio with unsaturated fatty acids, especially PUFAs of both n-6 and n-3 families. However, in presence of other factors such as positive energy balance, excessive intake of carbohydrates (in particular mono and disaccharides), and a sedentary lifestyle, the mechanisms to maintain a steady state of PA concentration may be disrupted leading to an over accumulation of tissue PA resulting in dyslipidemia, hyperglycemia, increased ectopic fat accumulation and increased inflammatory tone via toll-like receptor 4. It is therefore likely that the controversial data on the association of dietary PA with detrimental health effects, may be related to an excessive imbalance of dietary PA/PUFA ratio which, in certain physiopathological conditions, and in presence of an enhanced DNL, may further accelerate these deleterious effects.

N. Ferrara

D. McGehee, L. Role

F. Bazzaz

R. Burke, D. Levine, P. Tsairis et al.

M. Steriade, R. McCarley

Fareen Sami, M. Yusuf, M. Faizan et al.

Xiaohuan Mu, Yanling Chen

Nitrogen (N), as a macro-element, plays a vital role in plant growth and development. N deficiency affects plant productivity by decreasing photosynthesis, leaf area and longevity of green leaf. To date, many studies have reported that the relationship between photosynthesis and N supply. Here, we summarized the physiological response of photosynthesis to N deficiency in leaf structure and N allocation within the leaf. In serious N stress, photosynthetic rate decreases for almost all plants. The reasons as follows:(1) reducing stomatal conductance of mesophyll cell (gs) and bundle sheath cells (gbs) which influences intercellular CO2 concentration; (2) reducing the content of bioenergetics and light-harvesting protein which inhibits electron transport rate and increase the light energy dissipated as heat; (3) reducing the content and/or activity of photosynthetic enzymes which reduces carboxylation rate. During reproductive stage, N stress induces plant senescence and N components degradation, especially photosynthetic enzymes and thylakoid N, and thus reduces photosynthesis. To keep high grain yield in low N deficiency, we should choose the genotype with higher N allocation within bioenergetics and lower degradation of photosynthetic enzymes. This review provides a generalized N allocation in response to N stress and gives a new prospect for breeding N-efficient genotypes.

D. Huh, Y. Torisawa, G. Hamilton et al.

J. Speakman

R. Csapo, Matthias Gumpenberger, B. Wessner

Skeletal muscle represents the largest body-composition component in humans. In addition to its primary function in the maintenance of upright posture and the production of movement, it also plays important roles in many other physiological processes, including thermogenesis, metabolism and the secretion of peptides for communication with other tissues. Research attempting to unveil these processes has traditionally focused on muscle fibers, i.e., the contractile muscle cells. However, it is a frequently overlooked fact that muscle fibers reside in a three-dimensional scaffolding that consists of various collagens, glycoproteins, proteoglycans, and elastin, and is commonly referred to as extracellular matrix (ECM). While initially believed to be relatively inert, current research reveals the involvement of ECM cells in numerous important physiological processes. In interaction with other cells, such as fibroblasts or cells of the immune system, the ECM regulates muscle development, growth and repair and is essential for effective muscle contraction and force transmission. Since muscle ECM is highly malleable, its texture and, consequently, physiological roles may be affected by physical training and disuse, aging or various diseases, such as diabetes. With the aim to stimulate increased efforts to study this still poorly understood tissue, this narrative review summarizes the current body of knowledge on (i) the composition and structure of the ECM, (ii) molecular pathways involved in ECM remodeling, (iii) the physiological roles of muscle ECM, (iv) dysregulations of ECM with aging and disease as well as (v) the adaptations of muscle ECM to training and disuse.

T. Napso, Hannah E. J. Yong, J. López-Tello et al.

During pregnancy, the mother must adapt her body systems to support nutrient and oxygen supply for growth of the baby in utero and during the subsequent lactation. These include changes in the cardiovascular, pulmonary, immune and metabolic systems of the mother. Failure to appropriately adjust maternal physiology to the pregnant state may result in pregnancy complications, including gestational diabetes and abnormal birth weight, which can further lead to a range of medically significant complications for the mother and baby. The placenta, which forms the functional interface separating the maternal and fetal circulations, is important for mediating adaptations in maternal physiology. It secretes a plethora of hormones into the maternal circulation which modulate her physiology and transfers the oxygen and nutrients available to the fetus for growth. Among these placental hormones, the prolactin-growth hormone family, steroids and neuropeptides play critical roles in driving maternal physiological adaptations during pregnancy. This review examines the changes that occur in maternal physiology in response to pregnancy and the significance of placental hormone production in mediating such changes.

N. Maffiuletti

M. Costantine

Physiologic changes in pregnancy induce profound alterations to the pharmacokinetic properties of many medications. These changes affect distribution, absorption, metabolism, and excretion of drugs, and thus may impact their pharmacodynamic properties during pregnancy. Pregnant women undergo several adaptations in many organ systems. Some adaptations are secondary to hormonal changes in pregnancy, while others occur to support the gravid woman and her developing fetus. Some of the changes in maternal physiology during pregnancy include, for example, increased maternal fat and total body water, decreased plasma protein concentrations, especially albumin, increased maternal blood volume, cardiac output, and blood flow to the kidneys and uteroplacental unit, and decreased blood pressure. The maternal blood volume expansion occurs at a larger proportion than the increase in red blood cell mass, which results in physiologic anemia and hemodilution. Other physiologic changes include increased tidal volume, partially compensated respiratory alkalosis, delayed gastric emptying and gastrointestinal motility, and altered activity of hepatic drug metabolizing enzymes. Understating these changes and their profound impact on the pharmacokinetic properties of drugs in pregnancy is essential to optimize maternal and fetal health.

M. Karasek, K. Winczyk

Arturo Tozzi

Blood pressure regulation is commonly addressed in terms of local mechanisms such as vascular resistance, compliance and neurohumoral control. However, the human vasculature encompasses multiple quasi-closed flow loops under both physiological and pathological conditions. To test whether these loops could influence pressure dynamics beyond local control, we address the role of vascular topology in blood pressure regulation. Using one dimensional flow simulation models, we compared pressure dynamics in open vascular segments and closed vascular loops. We found that in open segments pressure fades away and remains spatially localized, whereas in closed loops pressure can keep circulating around the loop even if resistance in one spot is modified. Since parallel pathways within loops are dynamically coupled rather than independent, pressure changes in one place can affect the entire closed loop, allowing system level pressure patterns to emerge. Also, we assessed the temporal evolution of pressure fluctuations within closed vascular loops in normotensive and hypertensive parameter regimes, before and after loop breaking intervention. This topological approach helps clarifying why drugs or local interventions may fail to lower blood pressure in looped vascular architectures, providing a theoretical interpretation of some forms of resistant hypertension. Because disrupting a loop restores pressure relaxation, it may also help explain the disproportionate pressure changes observed after topology altering events like thrombosis, vascular surgery or embolization of arteriovenous malformations and shunts. Therefore, vascular topology can influence cardiovascular physiology by coupling local pressure flow relations to global constraints on blood pressure regulation, with physiological, pathological and clinical implications.

Zongzhe Xu, Zitao Shuai, Eideen Mozaffari et al.

We present SleepLM, a family of sleep-language foundation models that enable human sleep alignment, interpretation, and interaction with natural language. Despite the critical role of sleep, learning-based sleep analysis systems operate in closed label spaces (e.g., predefined stages or events) and fail to describe, query, or generalize to novel sleep phenomena. SleepLM bridges natural language and multimodal polysomnography, enabling language-grounded representations of sleep physiology. To support this alignment, we introduce a multilevel sleep caption generation pipeline that enables the curation of the first large-scale sleep-text dataset, comprising over 100K hours of data from more than 10,000 individuals. Furthermore, we present a unified pretraining objective that combines contrastive alignment, caption generation, and signal reconstruction to better capture physiological fidelity and cross-modal interactions. Extensive experiments on real-world sleep understanding tasks verify that SleepLM outperforms state-of-the-art in zero-shot and few-shot learning, cross-modal retrieval, and sleep captioning. Importantly, SleepLM also exhibits intriguing capabilities including language-guided event localization, targeted insight generation, and zero-shot generalization to unseen tasks. All code and data will be open-sourced.

Mustafa Ghulam, Ramin Mehrabifard, Adriana Mišúthová et al.

This study explores plasma-activated water (PAW) effects on Common bean growth in laboratory and pot trials. Three treatments were assessed: PAW priming, spraying, and their combination. Laboratory trials showed no germination improvement. However, pot trials revealed notable increases in seedling length, biomass, and antioxidant enzyme activity. Enzymes SOD, G-POX, CAT, APX, and GR showed significantly higher activity in PAW-treated plants. These effects were linked to reactive oxygen and nitrogen species in PAW. Findings suggest PAW enhances bean growth and physiology, supporting field farming applications.

Mo Wang, Kexin Zheng, Yingyue Xin et al.

Objective. Personalized transcranial electrical stimulation (tES) has gained growing attention due to the substantial inter-individual variability in brain anatomy and physiology. While previous reviews have discussed the physiological mechanisms and clinical applications of tES, there remains a critical gap in up-to-date syntheses focused on the computational modeling frameworks that enable individualized stimulation optimization. Approach. This review presents a comprehensive overview of recent advances in computational techniques supporting personalized tES. We systematically examine developments in forward modeling for simulating individualized electric fields, as well as inverse modeling approaches for optimizing stimulation parameters. We critically evaluate progress in head modeling pipelines, optimization algorithms, and the integration of multimodal brain data. Main results. Recent advances have substantially accelerated the construction of subject-specific head conductor models and expanded the landscape of optimization methods, including multi-objective optimization and brain network-informed optimization. These advances allow for dynamic and individualized stimulation planning, moving beyond empirical trial-and-error approaches.Significance. By integrating the latest developments in computational modeling for personalized tES, this review highlights current challenges, emerging opportunities, and future directions for achieving precision neuromodulation in both research and clinical contexts.

Catherine Kokemuller, Ryan Guldenpfennig, Clare Hsu et al.

Olive extract (OE) has been used in human foods for its nutraceutical effects, making it a product of interest for pet food. However, OE’s effect on palatability has not been examined. The study objective was to evaluate the palatability of dry cat foods with OE applied at differing inclusions within liquid or dry palatants. Twenty-seven volatile compounds were identified by gas chromatography–mass spectrometry for a potentially earthy or fruit-like flavor profile. Liquid palatants were formulated to supply 0 (control), 15, 30, 50, 75, and 150 ppm OE, and dry palatants were formulated to provide 0, 100, 200, 400, and 600 ppm OE when coated onto kibble. Palatability was evaluated using two-day, two-bowl testing of OE-containing versus control rations in adult cats (<i>n</i> = 20) with two-tailed <i>t</i>-tests to determine if OE affected intake ratio (IR). The observed IR of rations with OE were 0.45 to 0.56. The only preference was the 200 ppm treatment (IR = 0.56; <i>p</i> = 0.01) while the other OE rations were not different from the control (<i>p</i> ≥ 0.05). These findings indicate that palatant formulations can supply kibble diets with up to 150 ppm OE for liquid and 600 ppm for dry applications without negatively impacting cat food palatability.