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Phenomenological analysis of simple ion channel block in large populations of uncoupled cardiomyocytes

Simitev RD, Al Dawoud A, Aziz MHN, Myles R, Smith GL

Math Med Biol, 2023 Jun 14;40(2):175-198.
PMID: 36689769 DOI: 10.1093/imammb/dqad001

Current understanding of arrhythmia mechanisms and design of anti-arrhythmic drug therapies hinges on the assumption that myocytes from the same region of a single heart have similar, if not identical, action potential waveforms and drug responses. On the contrary, recent experiments reveal significant heterogeneity in uncoupled healthy myocytes both from different hearts as well as from identical regions within a single heart. In this work, a methodology is developed for quantifying the individual electrophysiological properties of large numbers of uncoupled cardiomyocytes under ion channel block in terms of the parameters values of a conceptual fast-slow model of electrical excitability. The approach is applied to a population of nearly 500 rabbit ventricular myocytes for which action potential duration (APD) before and after the application of the drug nifedipine was experimentally measured (Lachaud et al., 2022, Cardiovasc. Res.). To this end, drug action is represented by a multiplicative factor to an effective ion conductance, a closed form asymptotic expression for APD is derived and inverted to determine model parameters as functions of APD and $\varDelta $APD (drug-induced change in APD) for each myocyte. Two free protocol-related quantities are calibrated to experiment using an adaptive-domain procedure based on an original assumption of optimal excitability. The explicit APD expression and the resulting set of model parameter values allow (a) direct evaluation of conditions necessary to maintain fixed APD or $\varDelta $APD, (b) predictions of the proportion of cells remaining excitable after drug application, (c) predictions of stimulus period dependency and (d) predictions of dose-response curves, the latter being in agreement with additional experimental data.

Matched MeSH terms: Action Potentials/physiology
Single-trial extraction of event-related potentials (ERPs) and classification of visual stimuli by ensemble use of discrete wavelet transform with Huffman coding and machine learning techniques

Amin HU, Ullah R, Reza MF, Malik AS

J Neuroeng Rehabil, 2023 Jun 02;20(1):70.
PMID: 37269019 DOI: 10.1186/s12984-023-01179-8

BACKGROUND: Presentation of visual stimuli can induce changes in EEG signals that are typically detectable by averaging together data from multiple trials for individual participant analysis as well as for groups or conditions analysis of multiple participants. This study proposes a new method based on the discrete wavelet transform with Huffman coding and machine learning for single-trial analysis of evenal (ERPs) and classification of different visual events in the visual object detection task.
METHODS: EEG single trials are decomposed with discrete wavelet transform (DWT) up to the [Formula: see text] level of decomposition using a biorthogonal B-spline wavelet. The coefficients of DWT in each trial are thresholded to discard sparse wavelet coefficients, while the quality of the signal is well maintained. The remaining optimum coefficients in each trial are encoded into bitstreams using Huffman coding, and the codewords are represented as a feature of the ERP signal. The performance of this method is tested with real visual ERPs of sixty-eight subjects.
RESULTS: The proposed method significantly discards the spontaneous EEG activity, extracts the single-trial visual ERPs, represents the ERP waveform into a compact bitstream as a feature, and achieves promising results in classifying the visual objects with classification performance metrics: accuracies 93.60[Formula: see text], sensitivities 93.55[Formula: see text], specificities 94.85[Formula: see text], precisions 92.50[Formula: see text], and area under the curve (AUC) 0.93[Formula: see text] using SVM and k-NN machine learning classifiers.
CONCLUSION: The proposed method suggests that the joint use of discrete wavelet transform (DWT) with Huffman coding has the potential to efficiently extract ERPs from background EEG for studying evoked responses in single-trial ERPs and classifying visual stimuli. The proposed approach has O(N) time complexity and could be implemented in real-time systems, such as the brain-computer interface (BCI), where fast detection of mental events is desired to smoothly operate a machine with minds.

Matched MeSH terms: Evoked Potentials/physiology
Fulltext Sperm epigenetics landscape: correlation with embryo quality, reproductive outcomes and offspring's health

Garrido N, Boitrelle F, Saleh R, Durairajanayagam D, Colpi G, Agarwal A

Panminerva Med, 2023 Jun;65(2):166-178.
PMID: 37335245 DOI: 10.23736/S0031-0808.23.04871-1

Epigenetics refers to how gene expression and function are modulated without modifying the DNA sequence but through subtle molecular changes or interactions with it. As spermatogenesis progresses, male germ cells suffer plenty of epigenetic modifications, resulting in the definitive epigenome of spermatozoa conditioning its functionality, and this process can be altered by several internal and external factors. The paternal epigenome is crucial for sperm function, fertilization, embryo development, and offspring's health, and altered epigenetic states are associated with male infertility with or without altered semen parameters, embryo quality impairment, and worse ART outcomes together with the future offspring's health risks mainly through intergenerational transmission of epigenetic marks. Identifying epigenetic biomarkers may improve male factor diagnosis and the development of targeted therapies, not only to improve fertility but also to allow an early detection of risk and disease prevention in the progeny. While still there is much research to be done, hopefully in the near future, improvements in high-throughput technologies applied to epigenomes will permit our understanding of the underlying epigenetic mechanisms and the development of diagnostics and therapies leading to improved reproductive outcomes. In this review, we discuss the mechanisms of epigenetics in sperm and how epigenetics behave during spermatogenesis. Additionally, we elaborate on the relationship of sperm epigenetics with sperm parameters and male infertility, and highlight the impact of sperm epigenetic alterations on sperm parameters, embryo quality, ART outcomes, miscarriage rates and offspring's health. Furthermore, we provide insights into the future research of epigenetic alterations in male infertility.

Matched MeSH terms: Semen/physiology
Fulltext Cross-sectional interrelationships between chronotype, obstructive sleep apnea and blood pressure in a middle-aged community cohort

Sansom K, Reynolds A, Dhaliwal SS, Walsh J, Maddison K, Singh B, et al.

J Sleep Res, 2023 Jun;32(3):e13778.
PMID: 36330799 DOI: 10.1111/jsr.13778

Chronotype is linked to adverse health measures and may have important associations with obstructive sleep apnea and blood pressure, but data are limited. This study aimed to determine the separate and combined associations of chronotype with obstructive sleep apnea and blood pressure in a middle-aged community population. Adults (n = 811) from the Raine Study (female = 59.2%; age mean [range] = 56.6 [42.1-76.6] years) were assessed for chronotype (Morningness-Eveningness Questionnaire), blood pressure and hypertension (doctor diagnosed or systolic blood pressure ≥ 140 mmHg and/or diastolic ≥ 90 mmHg), and obstructive sleep apnea at different in-laboratory apnea-hypopnea index thresholds (5, 10, 15 events per hr). Linear and logistic regression models examined relationships between chronotype and the presence and severity of obstructive sleep apnea, blood pressure, hypertension, and blood pressure stratified by obstructive sleep apnea severity at above-mentioned apnea-hypopnea index thresholds. Covariates included age, sex, body mass index, alcohol consumption, smoking, physical activity, sleep duration, anti-hypertensive medication, insomnia, and depressive symptoms. Most participants were categorised as morning (40%) or intermediate (43%), with 17% meeting criteria for evening chronotypes. Participants with apnea-hypopnea index ≥ 15 events per hr and morning chronotype had higher systolic (9.9 mmHg, p

Matched MeSH terms: Blood Pressure/physiology; Sleep/physiology
Respiratory muscle training: a bibliometric analysis of 60 years' multidisciplinary journey

Ramli MI, Hamzaid NA, Engkasan JP, Usman J

Biomed Eng Online, 2023 May 22;22(1):50.
PMID: 37217941 DOI: 10.1186/s12938-023-01103-0

BACKGROUND: Over the decades, many publications have established respiratory muscle training (RMT) as an effective way in improving respiratory dysfunction in multiple populations. The aim of the paper is to determine the trend of research and multidisciplinary collaboration in publications related to RMT over the last 6 decades. The authors also sought to chart the advancement of RMT among people with spinal cord injury (SCI) over the last 60 years.
METHODS: Bibliometric analysis was made, including the publications' profiles, citation analysis and research trends of the relevant literature over the last 60 years. Publications from all time frames were retrieved from Scopus database. A subgroup analysis of publications pertinent to people with SCI was also made.
RESULTS: Research on RMT has been steadily increasing over the last 6 decades and across geographical locations. While medicine continues to dominate the research on RMT, this topic also continues to attract researchers and publications from other areas such as engineering, computer science and social science over the last 10 years. Research collaboration between authors in different backgrounds was observed since 2006. Source titles from non-medical backgrounds have also published articles pertinent to RMT. Among people with SCI, researchers utilised a wide range of technology from simple spirometers to electromyography in both intervention and outcome measures. With various types of interventions implemented, RMT generally improves pulmonary function and respiratory muscle strength among people with SCI.
CONCLUSIONS: While research on RMT has been steadily increasing over the last 6 decades, more collaborations are encouraged in the future to produce more impactful and beneficial research on people who suffer from respiratory disorders.

Matched MeSH terms: Respiratory Muscles/physiology
Fulltext Effects of powered ankle-foot orthoses mass distribution on lower limb muscle forces-a simulation study

Marconi G, Gopalai AA, Chauhan S

Med Biol Eng Comput, 2023 May;61(5):1167-1182.
PMID: 36689083 DOI: 10.1007/s11517-023-02778-2

This simulation study aimed to explore the effects of mass and mass distribution of powered ankle-foot orthoses, on net joint moments and individual muscle forces throughout the lower limb. Using OpenSim inverse kinematics, dynamics, and static optimization tools, the gait cycles of ten subjects were analyzed. The biomechanical models of these subjects were appended with ideal powered ankle-foot orthoses of different masses and actuator positions, as to determine the effect that these design factors had on the subject's kinetics during normal walking. It was found that when the mass of the device was distributed more distally and posteriorly on the leg, both the net joint moments and overall lower limb muscle forces were more negatively impacted. However, individual muscle forces were found to have varying results which were attributed to the flow-on effect of the orthosis, the antagonistic pairing of muscles, and how the activity of individual muscles affect each other. It was found that mass and mass distribution of powered ankle-foot orthoses could be optimized as to more accurately mimic natural kinetics, reducing net joint moments and overall muscle forces of the lower limb, and must consider individual muscles as to reduce potentially detrimental muscle fatigue or muscular disuse. OpenSim modelling method to explore the effect of mass and mass distribution on muscle forces and joint moments, showing potential mass positioning and the effects of these positions, mass, and actuation on the muscle force integral.

Matched MeSH terms: Ankle Joint/physiology; Biomechanical Phenomena/physiology; Gait/physiology; Walking/physiology; Muscle, Skeletal/physiology
Fulltext Activin A and pathologies of pregnancy: a review

Barber CV, Yo JH, Rahman RA, Wallace EM, Palmer KR, Marshall SA

Placenta, 2023 May;136:35-41.
PMID: 37028223 DOI: 10.1016/j.placenta.2023.03.008

Activin A is a two-subunit protein belonging to the transforming growth factor β superfamily. First discovered almost three decades ago, it has since been implicated in diverse physiological roles, ranging from wound repair to reproduction. After 30 years of research, altered activin A levels are now understood to be associated with the development of various diseases, making activin A a potential therapeutic target. In pregnancy, the placenta and fetal membranes are major producers of activin A, with significantly enhanced serum concentrations now recognised as a contributor to numerous gestational disorders. Evidence now suggests that circulating levels of activin A may be clinically relevant in the early detection of pregnancy complications, including miscarriage and preeclampsia. This review aims to summarise our current understanding of activin A as a potential diagnostic marker in common pregnancy pathologies.

Matched MeSH terms: Reproduction/physiology
Fulltext Aerobic Exercise Training Response in Preterm-Born Young Adults with Elevated Blood Pressure and Stage 1 Hypertension: A Randomized Clinical Trial

Burchert H, Lapidaire W, Williamson W, McCourt A, Dockerill C, Woodward W, et al.

Am J Respir Crit Care Med, 2023 May 01;207(9):1227-1236.
PMID: 36459100 DOI: 10.1164/rccm.202205-0858OC

Rationale: Premature birth is an independent predictor of long-term cardiovascular risk. Individuals affected are reported to have a lower rate of [Formula: see text]o2 at peak exercise intensity ([Formula: see text]o2PEAK) and at the ventilatory anaerobic threshold ([Formula: see text]o2VAT), but little is known about their response to exercise training. Objectives: The primary objective was to determine whether the [Formula: see text]o2PEAK response to exercise training differed between preterm-born and term-born individuals; the secondary objective was to quantify group differences in [Formula: see text]o2VAT response. Methods: Fifty-two preterm-born and 151 term-born participants were randomly assigned (1:1) to 16 weeks of aerobic exercise training (n = 102) or a control group (n = 101). Cardiopulmonary exercise tests were conducted before and after the intervention to measure [Formula: see text]o2PEAK and the [Formula: see text]o2VAT. A prespecified subgroup analysis was conducted by fitting an interaction term for preterm and term birth histories and exercise group allocation. Measurements and Main Results: For term-born participants, [Formula: see text]o2PEAK increased by 3.1 ml/kg/min (95% confidence interval [CI], 1.7 to 4.4), and the [Formula: see text]o2VAT increased by 2.3 ml/kg/min (95% CI, 0.7 to 3.8) in the intervention group versus controls. For preterm-born participants, [Formula: see text]o2PEAK increased by 1.8 ml/kg/min (95% CI, -0.4 to 3.9), and the [Formula: see text]o2VAT increased by 4.6 ml/kg/min (95% CI, 2.1 to 7.0) in the intervention group versus controls. No significant interaction was observed with birth history for [Formula: see text]o2PEAK (P = 0.32) or the [Formula: see text]o2VAT (P = 0.12). Conclusions: The training intervention led to significant improvements in [Formula: see text]o2PEAK and [Formula: see text]o2VAT, with no evidence of a statistically different response based on birth history. Clinical trial registered with www.clinicaltrials.gov (NCT02723552).

Matched MeSH terms: Exercise/physiology
Differences in right hemisphere fNIRS activation associated with executive network during performance of the lateralized attention network tast by elite, expert and novice ice hockey athletes

Yu M, Xu S, Hu H, Li S, Yang G

Behav Brain Res, 2023 Apr 12;443:114209.
PMID: 36368444 DOI: 10.1016/j.bbr.2022.114209

OBJECTIVE: We investigated brain activity associated with executive control attention network in elite, expert, and novice female ice hockey athletes during the revised lateralized attention network tast to determine whether the neural correlates of performance differ by skill level.
METHODS: We collected and analyzed functional near-infrared spectroscopy data of 38 participants while performing the revised lateralized attention network tast.
RESULTS: Elite players were significantly faster than novices (p = .005), and the experts' overall accuracy rate (ACC) was higher than that of novices (p = .001). The effect of the executive network on reaction time was higher in novices than in elite players (p = .008) and experts (p = .004). The effect of the executive network on the ACC was lower in elite players than in experts (p = .009) and novices (p = .010). Finally, elite player had higher flanker conflict effects on RT (p = .005) under the invalid cue condition. the effect of the alertness network and orientation on the ACC was lower in elite players than in novices (p = .000) and experts (p = .022). Changes in the blood oxygen level-dependent signal related to the flanker effect were significantly different in the right dorsolateral prefrontal cortex (F=3.980, p = .028) and right inferior frontal gyrus (F=3.703, p = .035) among the three groups. Elit players showed more efficient executive control (reduced conflict effect on ACC) (p = .006)in the RH.The changes related to the effect of blood oxygen level on orienting were significantly different in the right frontal eye fields (F=3.883, p = .030) among the three groups, Accompanied by significant activation of the right dorsolateral prefrontal cortex(p = .026).
CONCLUSION: Our findings provide partial evidence of the superior cognitive performance and high neural efficiency of elite ice hockey players during cognitive tasks. These results demonstrate the right hemisphere superiority for executive control.We also found that specific brain activation in hockey players does not show a clear and linear relationship with skill level.

Matched MeSH terms: Brain/physiology
Solutions to fire and shade: resprouting, growing tall and the origin of Eurasian temperate broadleaved forest

Adie H, Lawes MJ

Biol Rev Camb Philos Soc, 2023 Apr;98(2):643-661.
PMID: 36444419 DOI: 10.1111/brv.12923

Tree species of Eurasian broadleaved forest possess two divergent trait syndromes with contrasting patterns of resource allocation adapted to different selection environments: short-stature basal resprouters that divert resources to a bud bank adapted to frequent and severe disturbances such as fire and herbivory, and tall trees that delay reproduction by investing in rapid height growth to escape shading. Drawing on theory developed in savanna ecosystems, we propose a conceptual framework showing that the possession of contrasting trait syndromes is essential for the persistence of broadleaved trees in an open ecosystem that burns. Consistent with this hypothesis, trees of modern Eurasian broadleaved forest bear a suite of traits that are adaptive to surface and crown-fire regimes. We contend that limited opportunities in grassland restricts recruitment to disturbance-free refugia, and en masse establishment creates a wooded environment where shade limits the growth of light-demanding savanna plants. Rapid height growth, which involves investment in structural support and the switch from a multi-stemmed to a monopodial growth form, is adaptive in this shaded environment. Although clustering reduces surface fuel loads, these establishment nuclei are vulnerable to high-intensity crown fires. The lethal effects of canopy fire are avoided by seasonal leaf shedding, and aerial resprouting enhances rapid post-fire recovery of photosynthetic capacity. While these woody formations satisfy the structural definition of forest, their constituents are clearly derived from savanna. Contrasting trait syndromes thus represent the shift from consumer to resource regulation in savanna ecosystems. Consistent with global trends, the diversification of most contemporary broadleaved taxa coincided with the spread of grasslands, a surge in fire activity and a decline in wooded ecosystems in the late Miocene-Pliocene. Recognition that Eurasian broadleaved forest has savanna origins and persists as an alternative state with adjacent grassy ecosystems has far-reaching management implications in accordance with functional rather than structural criteria. Shade is a severe constraint to the regeneration and growth of both woody and herbaceous growth forms in consumer-regulated ecosystems. However, these ecosystems are highly resilient to disturbance, an essential process that maintains diversity especially among the species-rich herbaceous component that is vulnerable to shading when consumer behaviour is altered.

Matched MeSH terms: Trees/physiology
Influx of podoplanin-expressing inflammatory macrophages into the genital tract following Chlamydia infection

Chan YT, Cheok YY, Cheong HC, Tan GMY, Seow SR, Tang TF, et al.

Immunol Cell Biol, 2023 Apr;101(4):305-320.
PMID: 36658328 DOI: 10.1111/imcb.12621

Genital Chlamydia trachomatis infection remains a major health issue as it causes severe complications including pelvic inflammatory disease, ectopic pregnancy and infertility in females as a result of infection-associated chronic inflammation. Podoplanin, a transmembrane receptor, has been previously reported on inflammatory macrophages. Thus, strategies that specifically target podoplanin might be able to reduce local inflammation. This study investigated the expression level and function of podoplanin in a C. trachomatis infection model. C57BL/6 mice infected with the mouse pathogen Chlamydia muridarum were examined intermittently from days 1 to 60 using flow cytometry analysis. Percentages of conventional macrophages (CD11b+ CD11c- F4/80+ ) versus inflammatory macrophages (CD11b+ CD11c+ F4/80+ ), and the expression of podoplanin in these cells were investigated. Subsequently, a podoplanin-knockout RAW264.7 cell was used to evaluate the function of podoplanin in C. trachomatis infection. Our findings demonstrated an increased CD11b+ cell volume in the spleen at day 9 after the infection, with augmented podoplanin expression, especially among the inflammatory macrophages. A large number of podoplanin-expressing macrophages were detected in the genital tract of C. muridarum-infected mice. Furthermore, analysis of the C. trachomatis-infected patients demonstrated a higher percentage of podoplanin-expressing monocytes than that in the noninfected controls. Using an in vitro infection in a transwell migration assay, we identified that macrophages deficient in podoplanin displayed defective migratory function toward C. trachomatis-infected HeLa 229 cells. Lastly, using immunoprecipitation-mass spectrometry method, we identified two potential podoplanin interacting proteins, namely, Cofilin 1 and Talin 1 actin-binding proteins. The present study reports a role of podoplanin in directing macrophage migration to the chlamydial infection site. Our results suggest a potential for reducing inflammation in individuals with chronic chlamydial infections by targeting podoplanin.

Matched MeSH terms: Chlamydia trachomatis/physiology
Fulltext The effect of exercise in a fasted state on plasma low-density lipoprotein cholesterol concentrations in males and females

Bradshaw L, Koumanov F, Berry S, Betts JA, Gonzalez J

Exp Physiol, 2023 Apr;108(4):543-548.
PMID: 36809567 DOI: 10.1113/EP091005

Cardiovascular disease (CVD) is the leading cause of death worldwide. Physical activity interventions improve almost all modifiable CVD risk factors, but the effect of physical activity on low density lipoprotein cholesterol (LDL-C) is uncertain. This may be due to lack of research on the feeding status in which the physical activity is performed. The aim of this study is to investigate the effect of fasted versus fed exercise on LDL-C concentrations in males and females. One hundred healthy participants, equal males and females, aged between 25 and 60 years will be recruited and will undergo a home-based 12-week exercise intervention. After baseline testing, participants will be randomized to a fasted exercise (exercise after an 8-h fast) or fed exercise (exercise 90-180 min after ingestion of 1 g kg-1 CHO) group and will perform 50 min of moderate intensity exercise (e.g., 95% heart rate of lactate threshold 1) three times a week either before or after a high carbohydrate (1 g kg-1 ) meal. Participants will visit the laboratory again at week 4 and week 12 and measurements will be taken for body composition, resting blood pressure, fasting blood glucose, lipid profiles and systemic inflammation, lactate threshold, and 14-day blood glucose control.

Matched MeSH terms: Exercise/physiology
Fulltext Modelling the differential effects of age on transcranial magnetic stimulation induced electric fields

Alawi M, Lee PF, Deng ZD, Goh YK, Croarkin PE

J Neural Eng, 2023 Mar 16;20(2).
PMID: 36240726 DOI: 10.1088/1741-2552/ac9a76

Objective. The therapeutic application of noninvasive brain stimulation modalities such as transcranial magnetic stimulation (TMS) has expanded in terms of indications and patient populations. Often neurodevelopmental and neurodegenerative changes are not considered in research studies and clinical applications. This study sought to examine TMS dosing across time points in the life cycle.Approach. TMS induced electric fields with a figure-of-eight coil was simulated at left dorsolateral prefrontal cortex regions and taken in vertex as a control region. Realistic magnetic resonance imaging-based head models (N= 48) were concurrently examined in a cross-sectional study of three different age groups (children, adults, and elderlies).Main results. Age had a negative correlation with electric field peaks in white matter, grey matter and cerebrospinal fluid (P< 0.001). Notably, the electric field map in children displayed the widest cortical surface spread of TMS induced electric fields.Significance. Age-related anatomical geometry beneath the coil stimulation site had a significant impact on the TMS induced electric fields for different age groups. Safety considerations for TMS applications and protocols in children are warranted based on the present electric field findings.

Matched MeSH terms: Brain/physiology; Gray Matter/physiology
Ovarian lavage method as an alternative route for hormonal administration and short-term sperm storage in Clarias gariepinus

Okomoda VT, Amighty RO, Bem TM, Amaantimin J, Nurizzati I, Koh ICC, et al.

Theriogenology, 2023 Mar 01;198:203-209.
PMID: 36592519 DOI: 10.1016/j.theriogenology.2022.12.037

Ovarian lavage is a term used to describe the injection of fish with a catheter through the oviduct into the ovary. In this study, the efficacy of this technique was evaluated as a route for hormone administration and sperm preservation in the African catfish Clarias gariepinus. Firstly, the effects of hormone injection routes (namely, intramuscular, intraperitoneal, and ovarian lavage) were evaluated on breeding and haematological parameters. In the second study, the fish's spermatozoa were stored in the ovaries for 1, 2, 3, and 4 days before stripping, sperm activation with freshwater, and fertilization. The breeding performance was then compared with eggs fertilized using spermatozoa refrigerated for the same duration. The study showed that the administration of synthetic hormone (ovaprim®) through the ovaries was comparable to the intramuscular route, while those injected intraperitoneally had the least values (P 0.05) the fertilization (92-93%) and hatching (81-83%) of the eggs when compared to the control (91% and 82%). Beyond this 24hr threshold, breeding performances were significantly reduced in the ovarian lavage treatments compared to those fertilized with refrigerated sperm (P

Matched MeSH terms: Spermatozoa/physiology
Nocturnal hypoxia and the difference in morning and evening blood pressure measured at home

Azahar NM, Ganbaatar G, Kitaoka K, Sawayama Y, Yano Y

Hypertens Res, 2023 Mar;46(3):781-783.
PMID: 36642752 DOI: 10.1038/s41440-022-01164-z
Matched MeSH terms: Blood Pressure/physiology
Effect of Different Types of Aerobic Exercise on Individuals With and Without Hypertension: An Updated Systematic Review

Esmailiyan M, Amerizadeh A, Vahdat S, Ghodsi M, Doewes RI, Sundram Y

Curr Probl Cardiol, 2023 Mar;48(3):101034.
PMID: 34718034 DOI: 10.1016/j.cpcardiol.2021.101034

High blood pressure (BP) is one of the main modifiable risk factors for cardiovascular disease (CVD) and preventing it greatly reduces the vascular consequences of aging and, along with intensive treatment of hypertension, eliminates a large portion of the burden of CVD-related mortality. Many meta-analyses and studies proved that regular aerobic exercise (AE) reduces BP but most of these studies consider only hypertensive populations or only AE but not resistant exercise or their combination. In this review, we aimed to study the effect of different types of physical activity (PA)/AE on various populations including normotensive, prehypertensive, primary hypertensive, and resistant hypertensive with different comorbidities. We searched PubMed, Web of Science, and Google Scholar for English articles with keywords for physical activity, aerobic exercise, and blood pressure from January 2010 until September 2021. Finally, 24 studies were included. Results showed that chronic or acute AE (long-term or short-term), either alone or as combined with different sessions and programs can reduce systolic and diastolic BP in every group including normotensive, prehypertensive, primary hypertensive, resistant hypertensive individuals and diabetic patients and those with kidney problems but not in people with chronic heart failure. Isometric exercise training showed to be useful in reducing BP in all groups either as low intensity or as high intensity but the rate of reduction was different in terms of gender. AE showed to be effective in terms of BP reduction in a different age range. It can be seen that different types and duration of AE independent of the modality and programs and independent of the BP medical situation of individuals have been successful in terms of BP reduction. For those with chronic heart failure, more concern and help might be needed to decrease BP via exercise.

Matched MeSH terms: Blood Pressure/physiology; Exercise/physiology
Fulltext Using the Proteomics Toolbox to Resolve Topology and Dynamics of Compartmentalized cAMP Signaling

Kovanich D, Low TY, Zaccolo M

Int J Mol Sci, 2023 Feb 28;24(5).
PMID: 36902098 DOI: 10.3390/ijms24054667

cAMP is a second messenger that regulates a myriad of cellular functions in response to multiple extracellular stimuli. New developments in the field have provided exciting insights into how cAMP utilizes compartmentalization to ensure specificity when the message conveyed to the cell by an extracellular stimulus is translated into the appropriate functional outcome. cAMP compartmentalization relies on the formation of local signaling domains where the subset of cAMP signaling effectors, regulators and targets involved in a specific cellular response cluster together. These domains are dynamic in nature and underpin the exacting spatiotemporal regulation of cAMP signaling. In this review, we focus on how the proteomics toolbox can be utilized to identify the molecular components of these domains and to define the dynamic cellular cAMP signaling landscape. From a therapeutic perspective, compiling data on compartmentalized cAMP signaling in physiological and pathological conditions will help define the signaling events underlying disease and may reveal domain-specific targets for the development of precision medicine interventions.

Matched MeSH terms: Signal Transduction/physiology
Fulltext Flavonoids as Potential Wound-Healing Molecules: Emphasis on Pathways Perspective

Zulkefli N, Che Zahari CNM, Sayuti NH, Kamarudin AA, Saad N, Hamezah HS, et al.

Int J Mol Sci, 2023 Feb 27;24(5).
PMID: 36902038 DOI: 10.3390/ijms24054607

Wounds are considered to be a serious problem that affects the healthcare sector in many countries, primarily due to diabetes and obesity. Wounds become worse because of unhealthy lifestyles and habits. Wound healing is a complicated physiological process that is essential for restoring the epithelial barrier after an injury. Numerous studies have reported that flavonoids possess wound-healing properties due to their well-acclaimed anti-inflammatory, angiogenesis, re-epithelialization, and antioxidant effects. They have been shown to be able to act on the wound-healing process via expression of biomarkers respective to the pathways that mainly include Wnt/β-catenin, Hippo, Transforming Growth Factor-beta (TGF-β), Hedgehog, c-Jun N-Terminal Kinase (JNK), NF-E2-related factor 2/antioxidant responsive element (Nrf2/ARE), Nuclear Factor Kappa B (NF-κB), MAPK/ERK, Ras/Raf/MEK/ERK, phosphatidylinositol 3-kinase (PI3K)/Akt, Nitric oxide (NO) pathways, etc. Hence, we have compiled existing evidence on the manipulation of flavonoids towards achieving skin wound healing, together with current limitations and future perspectives in support of these polyphenolic compounds as safe wound-healing agents, in this review.

Matched MeSH terms: Wound Healing/physiology
Monitoring and modelling marine zooplankton in a changing climate

Ratnarajah L, Abu-Alhaija R, Atkinson A, Batten S, Bax NJ, Bernard KS, et al.

Nat Commun, 2023 Feb 02;14(1):564.
PMID: 36732509 DOI: 10.1038/s41467-023-36241-5

Zooplankton are major consumers of phytoplankton primary production in marine ecosystems. As such, they represent a critical link for energy and matter transfer between phytoplankton and bacterioplankton to higher trophic levels and play an important role in global biogeochemical cycles. In this Review, we discuss key responses of zooplankton to ocean warming, including shifts in phenology, range, and body size, and assess the implications to the biological carbon pump and interactions with higher trophic levels. Our synthesis highlights key knowledge gaps and geographic gaps in monitoring coverage that need to be urgently addressed. We also discuss an integrated sampling approach that combines traditional and novel techniques to improve zooplankton observation for the benefit of monitoring zooplankton populations and modelling future scenarios under global changes.

Matched MeSH terms: Phytoplankton/physiology
History of scurvy and use of vitamin C in critical illness: A narrative review

Dresen E, Lee ZY, Hill A, Notz Q, Patel JJ, Stoppe C

Nutr Clin Pract, 2023 Feb;38(1):46-54.
PMID: 36156315 DOI: 10.1002/ncp.10914

In 1747, an important milestone in the history of clinical research was set, as the Scottish surgeon James Lind conducted the first randomized controlled trial. Lind was interested in scurvy, a severe vitamin C deficiency which caused the death of thousands of British seamen. He found that a dietary intervention with oranges and lemons, which are rich in vitamin C by nature, was effective to recover from scurvy. Because of its antioxidative properties and involvement in many biochemical processes, the essential micronutrient vitamin C plays a key role in the human biology. Moreover, the use of vitamin C in critical illness-a condition also resulting in death of thousands in the 21st century-has gained increasing interest, as it may restore vascular responsiveness to vasoactive agents, ameliorate microcirculatory blood flow, preserve endothelial barriers, augment bacterial defense, and prevent apoptosis. Because of its redox potential and powerful antioxidant capacity, vitamin C represents an inexpensive and safe antioxidant, with the potential to modify the inflammatory cascade and improve clinical outcomes of critically ill patients. This narrative review aims to update and provide an overview on the role of vitamin C in the human biology and in critically ill patients, and to summarize current evidence on the use of vitamin C in diverse populations of critically ill patients, in specific focusing on patients with sepsis and coronavirus disease 2019.

Matched MeSH terms: Antioxidants/physiology

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