Hasil untuk "Physiology"

Alina Patke, M. W. Young, Sofia Axelrod

N. Maffiuletti, P. Aagaard, A. Blazevich et al.

The evaluation of rate of force development during rapid contractions has recently become quite popular for characterising explosive strength of athletes, elderly individuals and patients. The main aims of this narrative review are to describe the neuromuscular determinants of rate of force development and to discuss various methodological considerations inherent to its evaluation for research and clinical purposes. Rate of force development (1) seems to be mainly determined by the capacity to produce maximal voluntary activation in the early phase of an explosive contraction (first 50–75 ms), particularly as a result of increased motor unit discharge rate; (2) can be improved by both explosive-type and heavy-resistance strength training in different subject populations, mainly through an improvement in rapid muscle activation; (3) is quite difficult to evaluate in a valid and reliable way. Therefore, we provide evidence-based practical recommendations for rational quantification of rate of force development in both laboratory and clinical settings.

S. Negrão, Sandra M. Schmöckel, M. Tester

Background Because soil salinity is a major abiotic constraint affecting crop yield, much research has been conducted to develop plants with improved salinity tolerance. Salinity stress impacts many aspects of a plant’s physiology, making it difficult to study in toto. Instead, it is more tractable to dissect the plant’s response into traits that are hypothesized to be involved in the overall tolerance of the plant to salinity. Scope and conclusions We discuss how to quantify the impact of salinity on different traits, such as relative growth rate, water relations, transpiration, transpiration use efficiency, ionic relations, photosynthesis, senescence, yield and yield components. We also suggest some guidelines to assist with the selection of appropriate experimental systems, imposition of salinity stress, and obtaining and analysing relevant physiological data using appropriate indices. We illustrate how these indices can be used to identify relationships amongst the proposed traits to identify which traits are the most important contributors to salinity tolerance. Salinity tolerance is complex and involves many genes, but progress has been made in studying the mechanisms underlying a plant’s response to salinity. Nevertheless, several previous studies on salinity tolerance could have benefited from improved experimental design. We hope that this paper will provide pertinent information to researchers on performing proficient assays and interpreting results from salinity tolerance experiments.

Jing Li, B. Hou, Š. Tumová et al.

The mechanisms by which physical forces regulate endothelial cells to determine the complexities of vascular structure and function are enigmatic. Studies of sensory neurons have suggested Piezo proteins as subunits of Ca2+-permeable non-selective cationic channels for detection of noxious mechanical impact. Here we show Piezo1 (Fam38a) channels as sensors of frictional force (shear stress) and determinants of vascular structure in both development and adult physiology. Global or endothelial-specific disruption of mouse Piezo1 profoundly disturbed the developing vasculature and was embryonic lethal within days of the heart beating. Haploinsufficiency was not lethal but endothelial abnormality was detected in mature vessels. The importance of Piezo1 channels as sensors of blood flow was shown by Piezo1 dependence of shear-stress-evoked ionic current and calcium influx in endothelial cells and the ability of exogenous Piezo1 to confer sensitivity to shear stress on otherwise resistant cells. Downstream of this calcium influx there was protease activation and spatial reorganization of endothelial cells to the polarity of the applied force. The data suggest that Piezo1 channels function as pivotal integrators in vascular biology.

L. Romero

N. Terry, A. Zayed, M. P. D. Souza et al.

K. Ohtsubo, J. Marth

Glycosylation produces an abundant, diverse, and highly regulated repertoire of cellular glycans that are frequently attached to proteins and lipids. The past decade of research on glycan function has revealed that the enzymes responsible for glycosylation-the glycosyltransferases and glycosidases-are essential in the development and physiology of living organisms. Glycans participate in many key biological processes including cell adhesion, molecular trafficking and clearance, receptor activation, signal transduction, and endocytosis. This review discusses the increasingly sophisticated molecular mechanisms being discovered by which mammalian glycosylation governs physiology and contributes to disease.

Lippincott Williams Wilkins

H. Maturana, J. Lettvin, Warren Mcculloch et al.

Frogs arc essentially dependent on vision. They fccd on worms, flies, and other insects which they catch directly with the mouth or by striking them with the tongue; for this they use only visual clues. Furthermore, frogs prey only on moving insects, and their attention is never attracted by stationary creatures or objects. Nor do they respond with feeding behavior to a large moving object, instead it provokes an escape reaction. For them, a form deprived of movement SCClnS to bc behaviorally meaningless. Frogs, then, appear to recognize their prey and select it for attack from among all other environmental objects because it exhibits a number of features such as movement, a certain size, some contrast, and, perhaps, also a certain color. Furthermore, this ability of frogs to recognize their prey and to snap at it is not altered by changes in the general environment. Just as wc arc able to read and to recognize shapes under the most varied conditions, so arc frogs able to scc their prey and to fccd upon it under the bright light of midday or under the twilight of morning or evening, whether this bc in their natural environment or in a small cage in the laboratory. How is this accomplished? How do frogs recognize the universals, prey and enemy? To survive, a frog needs to react rapidly, either to catch a prey or to escape an enemy. To do this, the pat tern of light and dark that is the original image formed on the retina has to be anaJyzed, sooner or later, to select from it the features which define the universals. In these circumstances we can ask: Does the retina perform an analysis and abstract the meaningful parameters that will permit the recognition of the universals or is this analysis performed only later in the visual centers? Any

F. H. Adler

Jinghao Mu, Jian Xiong, Shunchang Zhou et al.

BackgroundEstrogen homeostasis is crucial for the structure and function of the urethra, and estrogen deprivation resulting from menopause, ovariectomy, or ovarian dysfunction may lead to various urethral dysfunctions. However, the specific molecular mechanisms involved are still not fully understood.MethodsUrethras from three ovariectomized (OVX) rats and three Sham rats were collected for snRNA-seq analysis. Data analysis included unsupervised clustering using the UMAP algorithm to identify distinct cell types based on marker gene expression. Differential gene expression analysis was performed to identify changes in estrogen-related gene expression across different cell types. Functional enrichment analysis was conducted to elucidate biological pathways associated with differentially expressed genes. Additionally, cellular interactions and developmental trajectories were analyzed to characterize cellular dynamics during menopause.ResultsHere, we profiled 69,529 single-nucleus transcriptomes from rat urethra (three OVX rats and three Sham rats). The snRNA-seq analysis revealed pronounced cellular heterogeneity and menopause-associated transcriptional reprogramming. We identified Fos as a key transcription factor associated with epithelial cell communication and differentiation under estrogen-deprived conditions. In addition, basal epithelial cells displayed EMT-associated transcriptional programs and a potential epithelial-to-mesenchymal continuum toward a mesenchymal-like state in OVX rats. We also identified Tmem233 as a hub gene in a striated muscle contraction-related module enriched in type IIa myofibers, and observed heightened inflammatory activation in immune cells, particularly T cells, in OVX rats.ConclusionIn summary, our study provides a comparative analysis of the snRNA-seq data from the urethra of female rats, elucidating cellular and molecular changes during menopause.

Mert Yetgın, Hale Yetgın, Hülya Sungurtekın

Abstract Positive end-expiratory pressure (PEEP) titration is crucial for preserving lung mechanics and physiology in mechanically ventilated patients. End-expiratory lung volume (EELV) and compliance can be used for this purpose. Based on these parameters, the Recruitment/Inflation ratio (R/I) has been used to estimate lung recruitability. We aimed to investigate the relationship between driving pressure and the Recruitment/Inflation ratio at two consecutive PEEP levels for appropriate PEEP selection in patients receiving mechanical ventilation support. End-expiratory lung volume (EELV) was measured during a decremental PEEP trial (PEEP levels of 20,15,10 and 5 cmH2O). The PEEP level associated with the lowest driving pressure among the four tested PEEP levels was selected. Patients were then ventilated at this selected PEEP level for 24 h. Subsequently, using the collected data, the R/I ratio was calculated between consecutive PEEP levels. If the R/I ratio was equal or above a pre-defined cut-off value, the higher of the two consecutive PEEP levels was considered potentially recruiting. If the R/I ratio was below the cut-off value, the lower PEEP level was considered appropriate. Finally, the relationship between the PEEP level associated with the lower driving pressure (between two consecutive PEEP steps) and the PEEP level deemed appropriate based on the R/I ratio cut-off was examined. The highest value of the arterial partial pressure of oxygen to fraction of inspired oxygen ratio (PaO2/FiO2) was measured at the 20 cmH2O PEEP level. EELV was found to be higher in patients classified as high recruiters (Step C and Step A) (P = 0.033). The PaO2/FiO2 ratio was also higher in the high-recruiter Step C (P = 0.008). In our study, the relationship between driving pressure and the R/I ratio for appropriate PEEP selection has been determined. The agreement between PEEP selection guided by driving pressure and PEEP selection guided by the R/I ratio did not reach statistical significance in our study. Sufficient and robust evidence to support the standalone use of the R/I ratio in clinical practice has not yet been established. Further studies are needed for this purpose.

Gábor Kőrösi, Oliver Czimbalmos, Gabriella Kekesi et al.

Abstract We present a high-throughput behavioral dataset acquired with Ambitus, an automated reward-based corridor system that records locomotor and exploratory activities and cognitive functions after minimal handling. The collection contains 91 raw and derived variables, each measured across four consecutive trials, for 1,342 Long-Evans rats, including a triple-hit schizophrenia-like substrain (Lisket) bred through 16 generations. All data files, detailed metadata and analysis scripts are openly available on Zenodo. This resource enables longitudinal and multivariate studies of behavioral phenotypes, trans-generational effects, and strain differences, and it provides a benchmark for machine-learning-based marker discovery in rodent models.

Y. Ruckebusch, P. Thivend

B. Fleshler

J. Thornley

Divya Nimma, Okram Ricky Devi, Bibek Laishram et al.

Global warming is a phenomenon whereby the planet's exposure to the sun's radiation worsens from the high emission of gasses believed to trap heat within the atmosphere. Carbon dioxide (CO2) is the leading greenhouse gas majorly responsible for global warming and other related issues and is a danger to global society. This one has a particular role in portraying the key importance of the shifting climate that invariably influences water supply and agricultural production. Global warming presents complex challenges to aquatic organisms and stocks and other natural aquatic life resources. This study examines how freshwater and marine species are affected by climate change in aquatic habitats. Aquatic species' metabolism, growth, reproduction, and dispersal are all impacted by rising temperatures and altered water chemistry brought on by increased greenhouse gas emissions, especially CO2. The goal is to pinpoint the ecosystems and vulnerable species that are most impacted by these changes and suggest flexible management techniques. The suggested remedies center on creating sustainable conservation strategies that lessen the effects of climate change on aquatic biodiversity and increase these ecosystems' resilience. The socio-economic interdependencies between water and climate change impact agricultural and water resources, and the pressures exerted on water bodies and water supply landscapes. Another area is related to alterations in the physical and chemical properties of the water, such as the temperature, which is a well-known effect of climate change: 'This causes abnormalities in the metabolism and physiology of aquatic species.' These alterations flow through the chain and regime of growth, reproduction, feeding habits and distribution, migration, and mass of fish and other creatures in the water system. However, the long-term effect of climate variation and climate change on freshwater ecosystems requires much scientific investigation to address challenges in aquatic ecosystem conservation and sustainability. This being the case, adaptive management solutions that address the interrelated impacts of climate change have to be applied and implemented to reduce vulnerability in aquatic ecosystems worldwide.

V. J. Wilson, G. Jones

Tatik Hernawati, Suherni Susilowati, Tri Wahyu Suprayogi et al.

One of the many efforts to increase the quality of livestock genetics is through artificial insemination (AI). Other than increasing it, AI can be conducted to preserve semen. A successful AI is determined by seminal quality, therefore, a method to preserve semen for a longer storage time is needed. The method used is adding an extender that fulfills prerequisites for a semen extender such as coconut water combined with egg yolk citrate extender. Coconut water is rich in carbohydrates, protein, vitamins, and antioxidants while egg yolk contains lecithin. This study aims to find out the Pote buck spermatozoa quality stored in coconut water and egg yolk extender. This study uses three groups of treatments (T0: 0.1 ml semen + 0.9 ml egg yolk citrate, T1: 0.1 ml semen + 0.9 ml coconut water, and T2: 0.1 ml semen + egg yolk citrate (20%) + coconut water). All three of these are stored at 5oC and evaluated every day until day 5 of their motility, viability, intact plasma membrane, abnormality, and MDA level. Data analysis used is ANOVA and a further test called BNT is conducted if a significant difference is determined. No significant difference was found between T0 and T1 (p>0.05). The highest progressive motility, viability, and intact plasma membrane (%) among the three groups of treatments happened to be from T2. Meanwhile, a low percentage of spermatozoa abnormality and MDA level were also found in T2 with its extender being coconut water combined with egg yolk citrate. To conclude, the best extender for storing Pote buck semen is stored at 5oC is coconut water combined with egg yolk citrate extender.

Cheryl S. Rosenfeld

The placenta operates during gestation as the primary communication organ between the mother and fetus. It is essential for gas, nutrient exchange, and fetal waste transfer. The placenta also produces a wide range of hormones and other factors that influence maternal physiology, including survival and activity of the corpus luteum of the ovary, but the means whereby the placenta shapes fetal development remain less clear, although the fetal brain is thought to be dependent upon the placenta for factors that play roles in its early differentiation and growth, giving rise to the term “placenta–brain axis”. Placental hormones transit via the maternal and fetal vasculature, but smaller placental molecules require protection from fetal and maternal metabolism. Such biomolecules include small RNA, mRNA, peptides, lipids, and catecholamines that include serotonin and dopamine. These compounds presumably shuttle to maternal and fetal systems via protective extracellular vesicles (EVs). Placental EVs (pEVs) and their components, in particular miRNA (miRs), are known to play important roles in regulating maternal systems, such as immune, cardiovascular, and reproductive functions. A scant amount is known about how pEVs affect fetal cells and tissues. The composition of pEVs can be influenced by gestational diseases. This review will provide critical insight into the roles of pEVs as the intermediary link between maternal and fetal systems, the impact of maternal pathologies on pEV cargo contents, and how an understanding of biomolecular changes within pEVs in health and disease might be utilized to design early diagnostic and mitigation strategies to prevent gestational diseases and later offspring disorders.