Metabolic Rate Research Articles

On the function and origin of the avian renal portal shunt and its potential significance throughout evolution.

All birds possess a unique venous architecture surrounding the kidneys known as the renal portal system. In veterinary medicine, this system is well known for causing a first-pass effect when medication is administered parenterally via the leg veins, that is venous blood from the leg is filtered before entering general circulation, thus possibly compromising adequate dosage. Additionally, bilateral valves are present in these veins, and it has been hypothesized that they play a crucial role in regulating flow through the kidneys to protect them against increases in blood pressure. While this hypothesis has been acknowledged, it has not been thoroughly explored. We propose that the function of the renal portal valve extends beyond its significance for kidney function, potentially impacting general hemodynamics. Examining anatomical similarities with extant non-avian reptiles, which lack the renal portal shunt with valve, could reveal additional functionalities of this system in birds. Given the endothermic metabolism and the energetically expensive locomotor activity of birds, the resistance of the hepatic and renal portal system might constrain the blood flow from splanchnic to non-splanchnic blood vessels necessary for (sustained) peak performance. Therefore, diverting blood from the renal portal system using the renal portal valve as a regulatory structure might represent a key adaptation to facilitate sustained peak performance. In addition, we hypothesize that this shunt and valve represents a very early adaptation in amniotes, possibly lost in extant non-avian reptiles but enhanced in birds, with a pivotal role in maintaining hemodynamic homeostasis to support the high metabolic rates characteristic of birds.

Human body temperature and cardiovascular response to changes in ambient temperature and body posture

Health problems due to heat or cold exposure is closely related not only to body temperature (BT) but also to blood flow rate (BFR) and blood pressure (BP). Therefore, it is necessary to understand the physiological mechanisms of the human body, such as how these physiological quantities change and how they affect each other. In this study, to clarify the physiological mechanisms of the human body, we measured the whole-body distribution of BT and BFR, as well as BP, heart rate, and metabolic rate under changes in ambient temperature and body posture. A total of 19 subjects were tested in three cases, including the temperature up-step and down-step cases, where the ambient temperature changed from 28 °C to 38 °C or 18 °C in the supine position, and the posture change case, where the posture changed alternately between the supine and standing positions at an ambient temperature of 28 °C. The results showed that the core temperature was efficiently maintained due to BFR regulation, especially in the extremities, in response to changes in ambient temperature. Additionally, changes in cerebral BFR in response to changes in posture were suppressed due to regulation of BFR, especially in the lower limbs, and heart rate. Furthermore, in the extremities, the BFR not only in the skin but also in the subcutaneous tissue and muscle was estimated to increase in hot environments and decrease in cold environments.

Life in the margins: the effect of immersion/emersion and tidal cycle on the North Atlantic limpet Patella vulgata protein synthesis rates.

Biological processes in intertidal species follow tidal rhythms that enhance survival and fitness. Whereas tidal effects on behaviour and metabolic rates have been widely studied, impacts on other key process such as protein synthesis are still poorly understood. To date, no studies have examined the effect of immersion/emersion and tidal cycles on protein synthesis rates (ks). Patella vulgata is an intertidal limpet present in North-Eastern Atlantic rocky shores from high to low shore. Previously reported P. vulgata respiration and heart rate measurements suggest aerobic metabolism is maintained during emersion and growth rates increase from high to low shore, but whether these patterns are reflected in ks is currently unclear. Here, we measured for the first time in any intertidal organism, ks, RNA to protein ratios and RNA translational efficiency (kRNA) in P. vulgata over a full tidal cycle, at three different shore heights. ks increased during emersion (p < 0.001) and was significantly higher in low shore animals compared to the other shore heights (p < 0.001), additionally ks was negatively correlated to body mass (p = 0.002). RNA to protein ratios remained unchanged over the tidal cycle (p = 0.659) and did not vary with shore height (p = 0.591). kRNA was significantly higher during emersion and was also higher in low shore limpets (p < 0.001). This study demonstrates that P. vulgata increases ks during emersion, an important adaptation in a species that spends a considerable amount of its lifecycle emersed. Intertidal species are highly exposed to increasing air temperatures, making knowledge of physiological responses during emersion critical in understanding and forecasting climate warming impacts.

Sarcosine, Trigonelline and Phenylalanine as Urinary Metabolites Related to Visceral Fat in Overweight and Obesity

The objective of the present study is to analyze the urinary metabolome profile of patients with obesity and overweight and relate it to different obesity profiles. This is a prospective, cross-sectional study in which patients with a body mass index (BMI) ≥25 kg/m were selected. Anthropometric data were assessed by physical examination and body composition was obtained by bioimpedance (basal metabolic rate, body fat percentile, skeletal muscle mass, gross fat mass and visceral fat). Urine was collected for metabolomic analysis. Patients were classified according to abdominal circumference measurements between 81 and 93, 94 and 104, and &gt;104 cm; visceral fat up to 16 kilos and less than; and fat percentiles of &lt;36%, 36–46% and &gt;46%. Spectral alignment of urinary metabolite signals and bioinformatic analysis were carried out to select the metabolites that stood out. NMR spectrometry was used to detect and quantify the main urinary metabolites and to compare the groups. Seventy-five patients were included, with a mean age of 38.3 years, and 72% females. The urinary metabolomic profile showed no differences in BMI, abdominal circumference and percentage of body fat. Higher concentrations of trigonelline (p = 0.0488), sarcosine (p = 0.0350) and phenylalanine (p = 0.0488) were associated with patients with visceral fat over 16 kg. The cutoff points obtained by the ROC curves were able to accurately differentiate between patients according to the amount of visceral fat: sarcosine 0.043 mg/mL; trigonelline 0.068 mg/mL and phenylalanine 0.204 mg/mL. In conclusion, higher visceral fat was associated with urinary levels of metabolites such as sarcosine, related to insulin resistance; trigonelline, related to muscle mass and strength; and phenylalanine, related to glucose metabolism and abdominal fat. Trigonelline, sarcosine and phenylalanine play significant roles in regulating energy balance and metabolic pathways essential for controlling obesity. Our findings could represent an interesting option for the non-invasive estimation of visceral fat through biomarkers related to alterations in metabolic pathways involved in the pathophysiology of obesity.

The Unique Morphofunctional Structure of the Reptilian Heart

The paper analyzes the evolution of the thermoenergetic statuses of vertebrates and the associated evolutionary development of their heart. The analysis shows that in most modern lepidosaurs and turtles, the heart is not completely, conditionally five-chambered: it has two atria and one ventricle, in which two incomplete septas divide it into three functional chambers. In some of them, these two septas were modified in evolution so that they turned into one with vertical and horizontal elements, as a result of which the heart became functionally four-chambered, with improved separation of arterial and venous blood flows. Crocodiles have a fully morphologically four-chambered heart. But the hearts of all reptiles, both recent and extinct, perform two opposite functions in parallel – the separation of arterial and venous blood flows and at the same time their regulated mixing. To do this, there are special morphological and physiological mechanisms in their hearts. Such a strange functional duality in the work of the reptilian heart aims to regulate the metabolism level by controlling the amount of carbon dioxide entering the blood flow: increasing the amount of CO2 in the blood flow reduces the metabolic rate, reducing its amount increase metabolism. Mixed blood in reptiles’ blood flow is not an immature, primitive state, but a physiological necessity. Moreover, this method of regulating of metabolic rate is most adequate to the initial, ancestral thermoenergetic state in reptiles, because basal terrestrial tetrapods and most ancient reptiles were meso- and even tachymetabolic, i.e. almost or completely warm-blooded, endothermic animals. It was just these endothermic animals that needed such type of metabolism regulation. As a result, all recent reptiles have a complex morphophysiological organization of the heart, which was functionally more suitable for their almost warm-blooded ancestors. Recent reptiles use part of their ancestral properties as an adaptation to new environmental conditions, new environmental requirements, and their new morphophysiological state. This unique organization of the heart is characteristic of all modern and extinct reptiles, and, importantly, it is characteristic exclusively for reptiles due to their original endothermic state.

The impact of isoflurane anesthesia on brain metabolism in mice: An MRI and electroencephalography study.

Isoflurane is one of the most widely used anesthetic agents in rodent imaging studies. However, the impact of isoflurane on brain metabolism has not been fully characterized to date, primarily due to a scarcity of noninvasive technologies to quantitatively measure the brain's metabolic rate in vivo. In this study, using noncontrast MRI techniques, we dynamically measured cerebral metabolic rate of oxygen (CMRO2) under varying doses of isoflurane anesthesia in mice. Concurrently, systemic parameters of heart and respiration rates were recorded alongside CMRO2. Additionally, electroencephalogram (EEG) recording was used to identify changes in neuronal activities under the same anesthetic regimen employed in the MRI experiments. We found suppression of the CMRO2 by isoflurane in a dose-dependent manner, concomitant with a diminished high-frequency EEG activity. The degree of metabolic suppression by isoflurane was strongly correlated with the respiration rate, which offers a potential approach to calibrate CMRO2 measurements. Furthermore, the metabolic level associated with neural responses of the somatosensory and motor cortices in mice was estimated as 308.2μmol/100 g/min. These findings may facilitate the integration of metabolic parameters into future studies involving animal disease models and anesthesia usage.

Time-restricted feeding modulates gene expression related with rhythm and inflammation in Mongolian gerbils

Time-restricted feeding (TRF) has the potential to modulate circadian rhythm and widely studied in humans and laboratory mice. However, less is known about the physiological responses to TRF in wild mammals. Here, we used Mongolian gerbils, Meriones unguiculatus, to explore the effect of 6-week TRF on gene expression related with circadian rhythm and inflammation. The TRF gerbils had higher cumulative food intake than the ad libitum (AL) group, but body mass, feeding frequency/time and metabolic rate did not differ between groups. In the hypothalamus, downregulation of rhythm-related genes Per3, Cry1 and Dbp was detected in the daytime-restricted feeding (DRF) group and Cry1 was downregulated in the nighttime-restricted feeding (NRF) group. In the liver, the expression of Per1/3, Rev-erbα/β and Dbp was lower, and Bmal1 was higher in the DRF than in AL group, while NRF gerbils showed no changes. In the colon, the expression of Bmal1 and Cry1 was higher but Per3, Rev-erbα/β and Dbp were lower in the DRF than in AL group. Further, the expression of inflammation-related genes such as NF-κB, IL-1β, IL-18 and Nlrp3 was lower in the liver of DRF gerbils, and IL-1β was lower both in the hypothalamus and liver of NRF gerbils. Moreover, the genes related with inflammation such as NF-κB, Nlrp3, IL-10/18/1β and Tnf-α were positively or negatively correlated with multiple rhythm-related genes in the central and peripheral organs. In conclusion, TRF, particularly DRF, could modulate rhythm-related genes in the central and peripheral tissues and reduce hepatic expression of inflammation-related genes in gerbils.

Impact of ginsenoside Rb1 on gut microbiome and associated changes in pharmacokinetics in rats

Ginsenoside Rb1 exhibits a wide range of biological activities, and gut microbiota is considered the main metabolic site for Rb1. However, the impact of gut microbiota on the pharmacokinetics of Rb1 are still uncertain. In this study, we investigated the gut microbiome changes and the pharmacokinetics after a 30 d Rb1 intervention. Results reveal that the systemic exposure and metabolic clearance rate of Rb1 and Rd were substantially affected after orally supplementing Rb1 (60 mg/kg) to rats. Significant increase in the relative abundance of Bacteroides cellulosilyticus in gut microbiota and specific glycoside hydrolase (GH) families, such as GH2, GH92, and GH20 were observed based on microbiome and metagenomic analysis. Moreover, a robust association was identified between the pharmacokinetic parameters of Rb1 and the relative abundance of specific Bacteroides species, and glycoside hydrolase families. Our study demonstrates that Rb1 administration significantly affects the gut microbiome, revealing a complex relationship between B. cellulosilyticus, key GH families, and Rb1 pharmacokinetics.

1,25‑Dihydroxyvitamin D3 mitigates the adipogenesis induced by bisphenol A in 3T3-L1 and hAMSC through miR-27-3p regulation.

Endocrine-disrupting compounds, including bisphenol A (BPA), may promote obesity influencing basal metabolic rate and shifting metabolism towards energy storage. The role of 1,25‑Dihydroxyvitamin D3 (VitD) in counteracting adipogenesis is still a matter of debate. Thus, the current study aims to investigate whether and how VitD exposure during adipogenesis could prevent the pro-adipogenic effect of BPA in two adipocyte models, mouse 3T3-L1 cell line and human adipose-derived mesenchymal stem cells (hAMSC). 3T3-L1, mouse pre-adipocytes and human adipose-derived mesenchymal stem cells (hAMSC) were treated with VitD (10-7 M) and BPA (10-8 M and 10-9 M), alone or in combination, throughout the differentiation in mature adipocytes. Cellular lipid droplet accumulation was assessed by Oil Red O staining, mRNA and protein expression of key adipogenic markers, transcription factors, and cytokines were investigated by RT-qPCR and WB, respectively. miRNAs involved in the regulation of adipogenic transcription factors were evaluated by RT-qPCR, and highly potent steric-blocking oligonucleotides (miRNA inhibitors) were used to modulate miRNAs expression. Pre-adipocytes express VitD receptor (VDR) in basal condition, but during the differentiation process VDR expression reduces if not stimulated by the ligand. VitD significantly decreases lipid accumulation, with a consequent reduction in adipogenic marker expression, and counteracts the pro-adipogenic effect of BPA in 3T3-L1 and hAMSC during differentiation. This effect is associated to the increased expression of miR-27a-3p and miR-27b-3p. The blocking of miR-27a-3p and miR-27b-3p through miRNA inhibitors prevents the anti-adipogenic effect of VitD in both cell models. These results suggest that in cultured 3T3-L1 and hAMSC VitD induces an anti-adipogenic effect and prevents BPA pro-adipogenic effect by triggering at least in part epigenetic mechanisms involving miR-27-3p.

Revealing the hidden threats: Genotoxic effects of microplastics on freshwater fish

New evidence regarding the risks that microplastics (MP) ingestion pose to human and wildlife health are being revealed with progress made in ecotoxicological research. However, comprehensive and realistic approaches that evaluate multiple physiological responses simultaneously are still scarce despite their relevance to understand whole-organism effects. To address this information gap, we performed an experiment to assess the effects of MP on freshwater fish physiology from the molecular to the organismal level. Using a model species of global commercial importance (Cyprinus carpio) and MP type (recycling industry fragments), size (range between 125-1000 µm), and two concentrations of environmental relevance (0.75 and 8.25 µg/L). Experimental design included 5 blocks containing 3 treatment levels each one: control, low, and high MP concentration, with 6 fish each aquarium (5 blocks x 3 treatments x 6 fish per aquarium = 90 fish). Our results suggest that, under the experimental conditions applied, MP exposure did not cause adverse effects at the morphological (variation in size of gut), metabolic (variation of standard metabolic rate), or ecological (growth performance) levels. Nonetheless, we observed an increased frequency of micronucleated cells with increasing MP concentration (df = 42, t-value = 3.68, p-value < 0.001), showing the potential genotoxicity of MP, which can clearly harm fish health in long-term. Thus, despite being a highly resistant species, exposure to MP may generate negative effects in juvenile C. carpio at cellular or subcellular levels. Our findings highlight that the manifestation of MP effects may vary over time, emphasizing the need for future studies to consider longer exposure durations in experimental designs.

Metabolic Stability and Metabolite Identification of CYP450 Probe Substrates in Ferret Hepatocytes.

Ferrets exhibit similar lung physiology to humans and display similar clinical signs following influenza infection, making them a valuable model for studying high susceptibility and infection patterns. However, the metabolic fate of several common human CYP450 probe substrates in ferrets is still unknown and has not been studied. The purpose of this study was to investigate the metabolism of nine human CYP450 probe substrates in ferret hepatocytes and explore their metabolic rate differences between ferrets and other species. Nine substrates were individually incubated in ferret hepatocytes for up to 120 min. At each time point, 30 μL mixtures were extracted for stability analysis using LC-MS/MS methods. After a 120-minute incubation period, 400 μL of the mixtures were extracted for metabolite identification using UHPLC-QExactive Plus. The metabolic clearance was determined as follows: diclofenac > taxol > chlorzoxazone > dextromethorphan > midazolam > omeprazole > bupropion > phenacetin > testosterone. Seven metabolites were identified from phenacetin. Deethylation was found to be the major pathway, and the major metabolite was matched with acetaminophen as probed with the CYP1A2 enzyme. Six metabolites were identified from diclofenac. Glucuronidation was the primary pathway, and a metabolite was found to match 4-OH-diclofenac as probed with the CYP2C9 enzyme. Twenty-two metabolites were identified from omeprazole. The major metabolic pathways included mono-oxygenation and sulfoxide to thioether conversion. No metabolite was found to match with the 5-OH-omeprazole as probed with the CYP2C19 enzyme. Twenty-two metabolites were identified from dextromethorphan. Demethylation was found to be the major metabolic pathway, and one demethylation metabolite was matched with dextrorphan as probed with CYP2D6. Fourteen metabolites were identified from midazolam. Mono-oxygenation was found to be the primary metabolic pathway, and one of the mono-oxygenation metabolites was matched with 1-OH-midazolam as probed with the CYP3A4 enzyme. Eight metabolites were identified from testosterone. Mono-oxygenation and glucuronidation were identified as the major metabolic pathways. One mono-oxygenation was matched with 6-β-testosterone as probed with CYP3A4 enzyme. Six metabolites were identified from taxol. Hydrolysis and mono-oxygenation were the top two metabolic pathways. No metabolite was matched with 6-α-OH-taxol as probed with the CYP2C8 enzyme. Ten metabolites were identified from bupropion. Mono-oxygenation and hydrogenation were identified as the top two metabolic pathways. No mono-oxygenation metabolite was matched with hydroxy-bupropion as probed with the CYP2B6 enzyme. Nine metabolites were identified from chlorzoxazone. Monooxygenation and sulfation were the top two metabolic pathways. One mono-oxygenation metabolite was matched with 6-OH-chlorzoxazone as probed with the CYP2E1 enzyme. Nine human CYP probe substrates were clearly metabolized in ferret hepatocytes, demonstrating substrate-dependent metabolic rates in ferret hepatocytes and species-dependent metabolic rates in mouse, rat, dog, monkey, and human hepatocytes. Except for 6-a-5-OH-omeprazole, 6-α-OH-taxol, and hydroxy-bupropion, specific metabolites of other six probe substrates in ferret hepatocytes were detected and identified as probed with six human CYP enzymes, respectively.

A Craniometric Analysis of the Subfamily Cervinae (Cervidae, Mammalia)

This study employs Principal Component Analysis to examine cranial measurements from both extant and fossil specimens spanning 38 species and comprising over 300 individuals within the subfamily Cervinae. Our findings elucidate craniometric distinctions among cervids characterized by varying body sizes and certain evolutionary adaptations. While our results generally corroborate previous assertions regarding the limited craniometric variability among plesiometacarpal deer, they also unveil specific cranial adaptations within certain genera and species. The Principal Component Analysis of craniometric data revealed that giant and large-sized deer display significantly broader ecomorphological diversity in cranial shape compared to small-sized deer. Secondly, small-sized deer exhibit greater uniformity in their cranial shape, appearing densely clustered on the factorial map. Thus, we conclude that body size imposes ecological constraints, limiting the available niches due to eco-physiological factors. This study demonstrates that endemic insular deer do not evolve consistent craniometric features attributable to insular isolation, while the cranial proportions of medium-to-small-sized deer delineate a ubiquitous morphological archetype characteristic of numerous cervid taxa spanning diverse phylogenetic lineages and sharing comparable body sizes. This group of “Dama-like” deer, characterized by similar body size, metabolic rates, ecological needs, and cranial morphometry, is referred to here as the fundamental eco-physiological type, typical of warm regions within the Palearctic and Oriental biogeographic realms.

Neuronal extracellular vesicles influence the expression, degradation and oligomeric state of fructose 1,6-bisphosphatase 2 in astrocytes affecting their glycolytic capacity

Fructose 1,6-bisphosphatase 2 (Fbp2) is a regulatory enzyme of gluco- and glyconeogenesis which, in the course of evolution, acquired non-catalytic functions. Fbp2 promotes cell survival during calcium stress, regulates glycolysis via inhibition of Hif-1α activity, and is indispensable for the formation of long-term potentiation in hippocampus. In hippocampal astrocytes, the amount of Fbp2 protein is reduced by signals delivered in neuronal extracellular vesicles (NEVs) through an unknown mechanism. The physiological role of Fbp2 (determined by its subcellular localization/interactions) depends on its oligomeric state and thus, we asked whether the cargo of NEVs is sufficient to change also the ratio of Fbp2 dimer/tetramer and, consequently, influence astrocyte basal metabolism. We found that the NEVs cargo reduced the Fbp2 mRNA level, stimulated the enzyme degradation and affected the cellular titers of different oligomeric forms of Fbp2. This was accompanied with increased glucose uptake and lactate release by astrocytes. Our results revealed that neuronal signals delivered to astrocytes in NEVs provide the necessary balance between enzymatic and non-enzymatic functions of Fbp2, influencing not only its amount but also subcellular localization. This may allow for the metabolic adjustments and ensure protection of mitochondrial membrane potential during the neuronal activity-related increase in astrocytic [Ca2+].

There is no limitation for CO2 excretion across the lung in exercising American alligators (Alligator mississippiensis).

Vertebrates utilize various respiratory organs like gills, lungs, and skin in combination with diverse cardiovascular structures, including single, three, and four-chambered hearts, to enable oxygen delivery and carbon dioxide removal. They also exhibit differences in aerobic and anaerobic metabolism during exertion, but the cardiorespiratory gas transport of all vertebrates follow is a similar a four-step process governed by Fick's Principle and Fick's Law of Diffusion over the entire range of metabolic rates. Hillman et al. (2013) suggested that previous exercise studies have focused too narrowly on mammals and proposed that the cardiorespiratory system's excess capacity serves an evolutionary role in enhancing CO2 excretion in non-mammalian vertebrates. In contrast, an analysis by Hicks and Wang (2021) concluded that vertebrates maintain effective gas exchange even at peak activity, finding no evidence of arterial hypercapnia at maximal oxygen consumption and thus challenging the proposal of significant limitations to pulmonary or branchial CO2 efflux. In the present study, we investigate the limits for CO2 exchange in exercising American alligators (Alligator mississippiensis) and provide evidence that the cardiorespiratory system is adequately built to sustain CO2 excretion during strenuous exercise and maintain arterial PCO2 , with no evidence of diffusion limitation for pulmonary CO2 excretion.

Predicting Steady-State Metabolic Power in Cerebral Palsy, Stroke, and the Elderly During Walking With and Without Assistive Devices.

Individuals with walking impairment, such as those with cerebral palsy, often face challenges in leading physically active lives due to the high energy cost of movement. Assistive devices like powered exoskeletons aim to alleviate this burden and improve mobility. Traditionally, optimizing the effectiveness of such devices has relied on time-consuming laboratory-based measurements of energy expenditure, which may not be feasible for some patient populations. To address this, our study aimed to enhance the state-of-the-art predictive model for estimating steady-state metabolic rate from 2-min walking trials to include individuals with and without walking disabilities and for a variety of terrains and wearable device conditions. Using over 200 walking trials collected from eight prior exoskeleton-related studies, we trained a simple linear machine learning model to predict metabolic power at steady state based on condition-specific factors, such as whether the trial was conducted on a treadmill (level or incline) or outdoors, as well as demographic information, such as the participant's weight or presence of walking impairment, and 2 minutes of metabolic data. We demonstrated the ability to predict steady-state metabolic rate to within an accuracy of 4.71 ± 2.7% on averageacross allwalking conditionsand patient populations, including with assistive devices andondifferent terrains. This work seeks to unlock the use of in-the-loop optimization of wearable assistive devices in individuals with limited walking capacity. A freely available MATLAB application allows other researchers to easily apply our model.

Metabolic Adaptation in Epilepsy: From Acute Response to Chronic Impairment.

Epilepsy is characterized by hypersynchronous neuronal discharges, which are associated with an increased cerebral metabolic rate of oxygen and ATP demand. Uncontrolled seizure activity (status epilepticus) results in mitochondrial exhaustion and ATP depletion, which potentially generate energy mismatch and neuronal loss. Many cells can adapt to increased energy demand by increasing metabolic capacities. However, acute metabolic adaptation during epileptic activity and its relationship to chronic epilepsy remains poorly understood. We elicited seizure-like events (SLEs) in an in vitro model of status epilepticus for eight hours. Electrophysiological recording and tissue oxygen partial pressure recordings were performed. After eight hours of ongoing SLEs, we used proteomics-based kinetic modeling to evaluate changes in metabolic capacities. We compared our findings regarding acute metabolic adaptation to published proteomic and transcriptomic data from chronic epilepsy patients. Epileptic tissue acutely responded to uninterrupted SLEs by upregulating ATP production capacity. This was achieved by a coordinated increase in the abundance of proteins from the respiratory chain and oxidative phosphorylation system. In contrast, chronic epileptic tissue shows a 25-40% decrease in ATP production capacity. In summary, our study reveals that epilepsy leads to dynamic metabolic changes. Acute epileptic activity boosts ATP production, while chronic epilepsy reduces it significantly.

Application Of Microbubble Technology To Increase Oxygen Content In The Aquaculture Of Tambaqui (Colossoma Macropomum)

The oxygen consumed is used to oxidize food substances to produce energy. Therefore, the metabolic rate is usually indicated by the rate of oxygen consumption per time unit. In most intensive aquaculture systems, oxygen content is widely used due to the high stocking density and maximum feeding rates. This study aimed to evaluate the growth performance of freshwater pomfret (Colossoma macropomum) treated with increased oxygen in two different systems. The study was conducted in a laboratory scale by applying T-test data analysis. The difference of treatment level applied in the comparison of aeration and microbubble consists of two treatments and three replications. The researcher used commercial floating pellets PF0 with 25% protein content, the feeding rate was 5% of the biomass. The feed was given daily during the culture for two times a day. Data of the study were analyzed using T-test on the Statistical Product and Service Solutions (SPSS) software Version 17.0. Results of the study showed that aeration system using microbubble resulted in dissolved oxygen (DO) of 6.5 ± 0.17, 100% pomfret fish survival rate (SR), Survival Growth Rate (SGR) of 1.83 ± 0.24, Feed Conversion Ratio (FCR) of 1.37 ± 0.17, Protein Efficiency Ratio (PER) of 2.79 ± 0.37, Feed Utilization Efficiency (FUE) of 0.67 ± 0.09, Absolute Weight Growth of 52.02 ± 1.60; it was better than using aeration. This study has developed a model of freshwater pomfret fish aquaculture to provide growth value.

Towards various occupants with different thermal comfort requirements: A deep reinforcement learning approach combined with a dynamic PMV model for HVAC control in buildings

Reinforcement learning (RL) has great potential in achieving energy-efficient, comfortable and intelligent control of heating, ventilation and air conditioning (HVAC) systems. Although research on RL-based HVAC control has attracted increasing interest, current studies generally use simple building simulation as the environment to train agents, and the definition of thermal comfort is limited to a wide temperature range, which cannot meet the different thermal comfort requirements of various occupants. This study proposes a deep reinforcement learning (DRL) control framework based on the Dueling Deep Q-network (DQN) algorithm, combined with a self-designed environmental model and reward function, for HVAC control meeting different thermal comfort requirements. Specifically, based on the theory of building thermal dynamics, a nonlinear equation modified by experimental data is used for the environmental model that reflects the actual thermal change of building. Different thermal comfort requirements are considered and analysed through a dynamic predicted mean vote (PMV) model that focuses on the metabolic rate and clothing level of occupants. By systematically exploring different heating modes for occupants and control time intervals, the proposed framework demonstrates that heating energy consumption can be reduced by 4.8%-39.58% under various conditions compared to rule-based control. In addition, the study found that the HVAC control based on DRL has greater potential in saving energy when the heating demand of building is higher. Our study is helpful for researchers to make HVAC control more energy-efficient and user-friendly with the help of artificial intelligence.

Metabolic adaptation following gastric bypass surgery: results from a 2-year observational study.

Metabolic adaptation is the lowering of basal metabolic rate (BMR) beyond what is predicted from changes in fat mass (FM) and fat-free mass (FFM) and may hamper weight-loss progression. It is unclear whether metabolic adaptation occurs following gastric bypass surgery (GBP) and if it persists. The aim of this study was to evaluate the reduction in BMR that is not explained by changes in body composition in patients following GBP compared to a weight-stable comparator group. Thirty-one patients [77.4% female; mean BMI 45.5(SD 7.0) kg/m2; age 47.4(11.6)y] who underwent GBP, and 32 time-matched comparators [50% female; BMI 27.2(4.6) kg/m2; age 41.8(13.6)y) were evaluated at 1-month pre-surgery, 3-, 12- and 24-months post-surgery. BMR was measured under standardised residential conditions using indirect calorimetry and body composition using DXA. Linear regression analyses assessed metabolic adaptation post-surgery. After surgery, patients lost a quarter of their body weight [-25.6%(1.8%); p < 0.0001] consisting mainly of FM (4:1 FM to FFM loss ratio) at 24-months post-surgery. Absolute BMR (MJ/d) reduced by 25.7% at 24-months post-surgery with values becoming similar to the comparator group from 3-months post-surgery. Positive associations were observed between changes in BMR and changes in FFM and FM (P < 0.03). Metabolic adaptation was present in patients during the 1) rapid weight loss phase (6.9 kg/month at 3-months post-surgery) (p = 0.011), 2) slower weight loss phase (1.6 kg/month from 3 to 12-months post-surgery) (p < 0.0001), and, 3) weight maintenance phase (24-months post-surgery) (p = 0.00073). However, the degree of metabolic adaptation observed in GBP patients was similar to the weight-stable comparator group (no metabolic adaptation) from 12-months post-surgery onwards (3-months; p = 0.01, 12-months; p = 0.26, 24-months post-surgery; p = 0.70). These results suggest that there is a potential biological mechanism of surgery that attenuates the expected postoperative downregulation in BMR thus helping GBP patients maintain weight loss.

Effects of FGF21 overexpression in osteoporosis and bone mineral density: a two-sample, mediating Mendelian analysis.

Fibroblast growth factor 21 (FGF21) is a secreted protein that regulates body metabolism. In recent years, many observational studies have found that FGF21 is closely related to bone mineral density and osteoporosis, but the causal relationship between them is still unclear. Therefore, this study used two-sample, mediated Mendelian randomization (MR) analysis to explore the causal relationship between FGF21 and osteoporosis and bone mineral density. We conducted a two-sample, mediator MR Analysis using genetic data from publicly available genome-wide association studies (GWAS) that included genetic variants in the inflammatory cytokine FGF21, and Total body bone mineral density, Heel bone mineral density, Forearm bone mineral density, Femoral neck bone mineral density, osteoporosis. The main analysis method used was inverse variance weighting (IVW) to investigate the causal relationship between exposure and outcome. In addition, weighted median, simple median method, weighted median method and MR-Egger regression were used to supplement the explanation, and sensitivity analysis was performed to evaluate the reliability of the results. MR Results showed that FGF21 overexpression reduced bone mineral density: Total body bone mineral density (OR=0.920, 95%CI: 0.876-0.966), P=0.001), Heel bone mineral density (OR=0.971, 95%CI (0.949-0.993); P=0.01), Forearm bone mineral density (OR=0.882, 95%CI(0.799-0.973); P=0.012), Femoral neck bone mineral density (OR=0.952, 95%CI(0.908-0.998), P=0.039); In addition, it also increased the risk of osteoporosis (OR=1.003, 95%CI (1.001-1.005), P=0.004). Sensitivity analysis supported the reliability of these results. The effect of FGF21 overexpression on osteoporosis may be mediated by type 2 diabetes mellitus and basal metabolic rate, with mediating effects of 14.96% and 12.21%, respectively. Our study suggests that the overexpression of FGF21 may lead to a decrease in bone mineral density and increase the risk of osteoporosis, and the effect of FGF21 on osteoporosis may be mediated through type 2 diabetes and basal metabolic rate. This study can provide a reference for analyzing the potential mechanism of osteoporosis and is of great significance for the prevention and treatment of osteoporosis.