Pub Date : 2024-05-16DOI: 10.3390/physiologia4020012
Ana Sofia Chaves, Filipe Silva, Ramiro Valentim, H. Quintas
Nutritional status plays a vital role in regulating ovary activity. This regulation is mediated by the hypothalamus–pituitary–gonad axis and by effects exerted directly on the ovary. Therefore, to achieve the best reproductive performance, it is essential to know how the nutritional status affects the secretion of GnRH, gonadotrophins, and sex steroid hormones. Adequate body reserves and energy balance are critical for optimal reproductive performance in sheep and goats. However, over- or under-conditioned animals experience issues like extended anestrus, irregular ovarian cycles, and reduced conception. Body condition scoring allows for the evaluation of the relationships between adiposity, nutritional status, and fertility. Acute feed deficits briefly stimulate processes, but chronic restrictions suppress pulsatile LH release, disrupting ovarian function. The process of follicle development is a very complex one which involves intricate interactions between the pituitary gonadotrophins and metabolic hormones as well as between the locally produced factors by the ovarian somatic and germ cells including the IGF system and the TGF-β superfamily members. Genotype and nutrition are factors that have an impact on follicular development, and seasonal factors are also involved. This review will give a brief overview on how the body condition can be evaluated and the effects of nutrition on the hypothalamus–pituitary–gonad axis and ovarian activity, which are responsible for reproductive regulation. This paper presents a clear and reasonable summary of the pathway that runs from the nutritional status of small ruminants to ovarian activity through the hypothalamic–pituitary–gonadal axis. This review summarizes methods for body condition evaluation in small ruminants and evidence regarding acute versus prolonged nutritional impacts on the hypothalamic–pituitary–gonadal axis and ovarian activity controlling reproduction.
{"title":"Body Condition in Small Ruminants—Effects of Nutrition on the Hypothalamic–Pituitary–Gonad Axis and Ovarian Activity That Controls Reproduction","authors":"Ana Sofia Chaves, Filipe Silva, Ramiro Valentim, H. Quintas","doi":"10.3390/physiologia4020012","DOIUrl":"https://doi.org/10.3390/physiologia4020012","url":null,"abstract":"Nutritional status plays a vital role in regulating ovary activity. This regulation is mediated by the hypothalamus–pituitary–gonad axis and by effects exerted directly on the ovary. Therefore, to achieve the best reproductive performance, it is essential to know how the nutritional status affects the secretion of GnRH, gonadotrophins, and sex steroid hormones. Adequate body reserves and energy balance are critical for optimal reproductive performance in sheep and goats. However, over- or under-conditioned animals experience issues like extended anestrus, irregular ovarian cycles, and reduced conception. Body condition scoring allows for the evaluation of the relationships between adiposity, nutritional status, and fertility. Acute feed deficits briefly stimulate processes, but chronic restrictions suppress pulsatile LH release, disrupting ovarian function. The process of follicle development is a very complex one which involves intricate interactions between the pituitary gonadotrophins and metabolic hormones as well as between the locally produced factors by the ovarian somatic and germ cells including the IGF system and the TGF-β superfamily members. Genotype and nutrition are factors that have an impact on follicular development, and seasonal factors are also involved. This review will give a brief overview on how the body condition can be evaluated and the effects of nutrition on the hypothalamus–pituitary–gonad axis and ovarian activity, which are responsible for reproductive regulation. This paper presents a clear and reasonable summary of the pathway that runs from the nutritional status of small ruminants to ovarian activity through the hypothalamic–pituitary–gonadal axis. This review summarizes methods for body condition evaluation in small ruminants and evidence regarding acute versus prolonged nutritional impacts on the hypothalamic–pituitary–gonadal axis and ovarian activity controlling reproduction.","PeriodicalId":93484,"journal":{"name":"Physiologia","volume":"18 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140967440","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-17DOI: 10.3390/physiologia4020010
Verayna Newland, Lauren L. Jantzie, Bonnie L. Blazer-Yost
Hydrocephalus is caused by an overproduction of cerebrospinal fluid (CSF), an obstruction of fluid movement, or improper reabsorption. CSF accumulation in the brain’s ventricles causes ventriculomegaly, increased intracranial pressure, inflammation, and neural cell injury. Hydrocephalus can arise from brain trauma, hemorrhage, infection, tumors, or genetic mutations. Currently, there is no cure for hydrocephalus. Treatments like shunting and endoscopic third ventriculostomies are used, but, unfortunately, these therapeutic approaches require brain surgery and have high failure rates. The choroid plexus epithelium (CPe) is thought to be the major producer of CSF in the brain. It is a polarized epithelium that regulates ion and water movement from a fenestrated capillary exudate to the ventricles. Despite decades of research, control of electrolyte movement in the CPe is still not fully understood. This review discusses important transporters on the CPe, how some of these are regulated, and which of them could be potential targets for hydrocephalus treatment. To advance the development of hydrocephalus treatments, physiologically relevant preclinical models are crucial. This review covers some of the current animal and cell culture methods used to study hydrocephalus and highlights the need to develop standardized preclinical models that are used by multiple investigators in order to replicate critical findings and resolve controversies regarding potential drug targets.
{"title":"Understanding and Modeling the Pathophysiology of Hydrocephalus: In Search of Better Treatment Options","authors":"Verayna Newland, Lauren L. Jantzie, Bonnie L. Blazer-Yost","doi":"10.3390/physiologia4020010","DOIUrl":"https://doi.org/10.3390/physiologia4020010","url":null,"abstract":"Hydrocephalus is caused by an overproduction of cerebrospinal fluid (CSF), an obstruction of fluid movement, or improper reabsorption. CSF accumulation in the brain’s ventricles causes ventriculomegaly, increased intracranial pressure, inflammation, and neural cell injury. Hydrocephalus can arise from brain trauma, hemorrhage, infection, tumors, or genetic mutations. Currently, there is no cure for hydrocephalus. Treatments like shunting and endoscopic third ventriculostomies are used, but, unfortunately, these therapeutic approaches require brain surgery and have high failure rates. The choroid plexus epithelium (CPe) is thought to be the major producer of CSF in the brain. It is a polarized epithelium that regulates ion and water movement from a fenestrated capillary exudate to the ventricles. Despite decades of research, control of electrolyte movement in the CPe is still not fully understood. This review discusses important transporters on the CPe, how some of these are regulated, and which of them could be potential targets for hydrocephalus treatment. To advance the development of hydrocephalus treatments, physiologically relevant preclinical models are crucial. This review covers some of the current animal and cell culture methods used to study hydrocephalus and highlights the need to develop standardized preclinical models that are used by multiple investigators in order to replicate critical findings and resolve controversies regarding potential drug targets.","PeriodicalId":93484,"journal":{"name":"Physiologia","volume":"2 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140693043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-04-08DOI: 10.3390/physiologia4020009
Nonkululeko Avril Mbatha, A. G. Mushebenge, A. Khathi
Prediabetes, a pivotal phase in glucose metabolism between normalcy and diabetes, exerts a profound influence on the aging process and the risk of age-related diseases. This comprehensive review delves into the intricate web of blood-based biomarkers that collectively expedite senescence, marking the transition from a state of health to age-related complications. Key findings underscore the significance of diverse biomarkers, such as telomere length, p16INK4a, senescence-associated secretory phenotype (SASP) factors, DNA methylation clocks, advanced glycation end products (AGEs), inflammatory and oxidative stress markers, circulating hormones, and additional factors such as folate, B12, and osteocalcin. Not only do these biomarkers serve as indicators of senescence but they also actively fuel chronic inflammation, oxidative stress, and metabolic dysregulation, all of which contribute to accelerated aging. The implications of this understanding are profound, as prediabetes emerges as a critical period in an individual’s life, influencing various physiological systems, including the vascular and neural systems, metabolic functions, hormonal regulation, and bone health. Recognizing the profound influence of prediabetes on senescence provides a foundation for personalized intervention strategies to mitigate age-related complications and promote healthy aging. Future research directions call for a more diverse array of biomarkers, the in-depth exploration of their roles, and the development of tailored precision medicine strategies to ensure a holistic understanding and effective management of prediabetes-induced senescence and its implications for aging. This knowledge has far-reaching implications for public health and clinical practice, emphasizing the need for early detection and intervention in prediabetic individuals to enhance the quality of life in an aging population with diverse needs.
{"title":"Identification of Putative Causal Relationships between Blood-Based Biomarkers and Prediabetes-Induced Senescence: A Comprehensive Review","authors":"Nonkululeko Avril Mbatha, A. G. Mushebenge, A. Khathi","doi":"10.3390/physiologia4020009","DOIUrl":"https://doi.org/10.3390/physiologia4020009","url":null,"abstract":"Prediabetes, a pivotal phase in glucose metabolism between normalcy and diabetes, exerts a profound influence on the aging process and the risk of age-related diseases. This comprehensive review delves into the intricate web of blood-based biomarkers that collectively expedite senescence, marking the transition from a state of health to age-related complications. Key findings underscore the significance of diverse biomarkers, such as telomere length, p16INK4a, senescence-associated secretory phenotype (SASP) factors, DNA methylation clocks, advanced glycation end products (AGEs), inflammatory and oxidative stress markers, circulating hormones, and additional factors such as folate, B12, and osteocalcin. Not only do these biomarkers serve as indicators of senescence but they also actively fuel chronic inflammation, oxidative stress, and metabolic dysregulation, all of which contribute to accelerated aging. The implications of this understanding are profound, as prediabetes emerges as a critical period in an individual’s life, influencing various physiological systems, including the vascular and neural systems, metabolic functions, hormonal regulation, and bone health. Recognizing the profound influence of prediabetes on senescence provides a foundation for personalized intervention strategies to mitigate age-related complications and promote healthy aging. Future research directions call for a more diverse array of biomarkers, the in-depth exploration of their roles, and the development of tailored precision medicine strategies to ensure a holistic understanding and effective management of prediabetes-induced senescence and its implications for aging. This knowledge has far-reaching implications for public health and clinical practice, emphasizing the need for early detection and intervention in prediabetic individuals to enhance the quality of life in an aging population with diverse needs.","PeriodicalId":93484,"journal":{"name":"Physiologia","volume":"48 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140731833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-02-17DOI: 10.3390/physiologia4010006
Katarzyna Piotrowska, Maciej Tarnowski, Patrycja Tomasiak, M. Czerewaty, K. Zgutka, Andrzej Pawlik
Background: The positive effects of prolonged every-other-day (EOD) feeding include decreased body weight and prolonged life span, but also changes in liver metabolism and functions. In the present paper, our aim was to examine the expression of adiponectin (ADIPOQ), leptin, and their receptors (ADIPOR1, ADIPOR2, and LEPR) in the liver tissue of EOD-fed mice in comparison to ad libitum (AL)-treated mice. Methods: After 9 months of EOD treatment, liver tissue was harvested and prepared for analysis. RT-PCR, protein semi-quantitative estimation, and cellular immunolocalization was performed. Results: We noted a decreased expression of leptin in the liver tissue of the EOD male mice in comparison to the AL mice on the protein level. ADIPOQ receptor R1 protein expression was decreased in the liver of EOD-fed male mice, while the expression of ADIPOR2 on the protein level was increased in the EOD animals. Conclusions: To the best of our knowledge, this is the first report showing ADIPOQ and leptin immunolocalization in the liver tissue in a dietary regime experiment. Decreases in leptin expression and IL-6 expression in liver tissue and increases in ADIPOR2 expression may be partly responsible for the beneficial effects of EOD treatment in the liver, including the decrease in inflammation. Further studies are needed to establish whether these changes depend on factors like the type of treatment, species, strain, gender, time of treatment, and others.
{"title":"Decrease in Leptin Expression in the Liver after Prolonged Every-Other-Day Feeding in C57Bl/6 Male Mice","authors":"Katarzyna Piotrowska, Maciej Tarnowski, Patrycja Tomasiak, M. Czerewaty, K. Zgutka, Andrzej Pawlik","doi":"10.3390/physiologia4010006","DOIUrl":"https://doi.org/10.3390/physiologia4010006","url":null,"abstract":"Background: The positive effects of prolonged every-other-day (EOD) feeding include decreased body weight and prolonged life span, but also changes in liver metabolism and functions. In the present paper, our aim was to examine the expression of adiponectin (ADIPOQ), leptin, and their receptors (ADIPOR1, ADIPOR2, and LEPR) in the liver tissue of EOD-fed mice in comparison to ad libitum (AL)-treated mice. Methods: After 9 months of EOD treatment, liver tissue was harvested and prepared for analysis. RT-PCR, protein semi-quantitative estimation, and cellular immunolocalization was performed. Results: We noted a decreased expression of leptin in the liver tissue of the EOD male mice in comparison to the AL mice on the protein level. ADIPOQ receptor R1 protein expression was decreased in the liver of EOD-fed male mice, while the expression of ADIPOR2 on the protein level was increased in the EOD animals. Conclusions: To the best of our knowledge, this is the first report showing ADIPOQ and leptin immunolocalization in the liver tissue in a dietary regime experiment. Decreases in leptin expression and IL-6 expression in liver tissue and increases in ADIPOR2 expression may be partly responsible for the beneficial effects of EOD treatment in the liver, including the decrease in inflammation. Further studies are needed to establish whether these changes depend on factors like the type of treatment, species, strain, gender, time of treatment, and others.","PeriodicalId":93484,"journal":{"name":"Physiologia","volume":"211 ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-02-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140453298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-12-13DOI: 10.3390/physiologia3040046
Julius Granlund, H. Kyröläinen, M. Santtila, B. C. Nindl, K. Pihlainen, T. Ojanen
The objective of the present review was to evaluate the time-course of recovery of biochemical marker levels and physical performance after strenuous military training, and identify which biomarkers are affected. A systematic literature search was conducted using the databases MedLine (Ovid) and Web of Science (WoS) to identify studies until January 2023. Varying relevant search terms were used, related to military training, Special Forces, physical performance, and biomarkers. Records were based on strict inclusion and exclusion criteria. Twelve studies met the inclusion criteria and were selected for this review. A variety of physiological and psychological markers were measured, and military training lasted from 4 to 62 days, with recovery periods varying from 24 h to 6 weeks. Among these studies, full recovery was observed in two studies, while seven studies showed almost full (79–90%) recovery, and in three studies, 44–63% of markers recovered after the measured recovery period. However, in some studies, additional markers could be defined as recovered, depending on the criterion for recovery. In the majority of the studies, most of the measured variables recovered during the follow-up, but often, some variables remained unrecovered, and at times, only modest recovery was seen. It is important to point out that recovery duration depends on the duration and intensity of the military training stressor. Overall, resolution varies between the markers, and sometimes, recovery might not occur, even after prolonged recovery. Therefore, it is important to measure the recovery status of soldiers with both biomarkers and physical performance markers, especially after strenuous training, to maximize operational capability during prolonged missions.
{"title":"Time-Course of Recovery for Biomarkers and Physical Performance after Strenuous Military Training: A Systematic Review","authors":"Julius Granlund, H. Kyröläinen, M. Santtila, B. C. Nindl, K. Pihlainen, T. Ojanen","doi":"10.3390/physiologia3040046","DOIUrl":"https://doi.org/10.3390/physiologia3040046","url":null,"abstract":"The objective of the present review was to evaluate the time-course of recovery of biochemical marker levels and physical performance after strenuous military training, and identify which biomarkers are affected. A systematic literature search was conducted using the databases MedLine (Ovid) and Web of Science (WoS) to identify studies until January 2023. Varying relevant search terms were used, related to military training, Special Forces, physical performance, and biomarkers. Records were based on strict inclusion and exclusion criteria. Twelve studies met the inclusion criteria and were selected for this review. A variety of physiological and psychological markers were measured, and military training lasted from 4 to 62 days, with recovery periods varying from 24 h to 6 weeks. Among these studies, full recovery was observed in two studies, while seven studies showed almost full (79–90%) recovery, and in three studies, 44–63% of markers recovered after the measured recovery period. However, in some studies, additional markers could be defined as recovered, depending on the criterion for recovery. In the majority of the studies, most of the measured variables recovered during the follow-up, but often, some variables remained unrecovered, and at times, only modest recovery was seen. It is important to point out that recovery duration depends on the duration and intensity of the military training stressor. Overall, resolution varies between the markers, and sometimes, recovery might not occur, even after prolonged recovery. Therefore, it is important to measure the recovery status of soldiers with both biomarkers and physical performance markers, especially after strenuous training, to maximize operational capability during prolonged missions.","PeriodicalId":93484,"journal":{"name":"Physiologia","volume":"191 S529","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139006413","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-08DOI: 10.3390/physiologia3040042
Sumedha Shastry, David Mizrahi, Grace Kanzawa-Lee
Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting side-effect resulting from numerous neurotoxic chemotherapies that damages the peripheral nerves, alters sensations in the hands and feet, causes burning and shooting pains, and impairs a patient’s quality of life (QoL). There are limited established interventions to help improve CIPN symptoms. There is only one pharmacological agent (Duloxetine) for treatment of CIPN; however, it only has mild benefit, signaling a critical need for alternative management options to manage patient symptoms. Multiple studies suggest therapeutic benefits of exercise in cancer care to improve physical and psychological functioning; however, the benefits regarding CIPN symptoms and physical function are less clear. This narrative review synthesizes research articles investigating the effect and mechanisms induced by different exercise programs for patients with taxane-induced peripheral neuropathy (TIPN) symptoms and function. The overall incidence, manifestations, characteristics, and mechanisms of CIPN are also discussed. While some studies in this narrative review demonstrated that exercise programs may have benefits on sensory and motor TIPN symptoms in some but not all patients, there are consistent benefits of improved QoL and physical function across most patients. This narrative review highlights the need for future research to confirm the effects of exercise for TIPN, with a focus on other important components, including the effect of exercise adherence, type, and supervision level.
{"title":"The Future of Chemotherapy: The Mechanisms and Benefits of Exercise in Taxane-Induced Peripheral Neuropathy","authors":"Sumedha Shastry, David Mizrahi, Grace Kanzawa-Lee","doi":"10.3390/physiologia3040042","DOIUrl":"https://doi.org/10.3390/physiologia3040042","url":null,"abstract":"Chemotherapy-induced peripheral neuropathy (CIPN) is a dose-limiting side-effect resulting from numerous neurotoxic chemotherapies that damages the peripheral nerves, alters sensations in the hands and feet, causes burning and shooting pains, and impairs a patient’s quality of life (QoL). There are limited established interventions to help improve CIPN symptoms. There is only one pharmacological agent (Duloxetine) for treatment of CIPN; however, it only has mild benefit, signaling a critical need for alternative management options to manage patient symptoms. Multiple studies suggest therapeutic benefits of exercise in cancer care to improve physical and psychological functioning; however, the benefits regarding CIPN symptoms and physical function are less clear. This narrative review synthesizes research articles investigating the effect and mechanisms induced by different exercise programs for patients with taxane-induced peripheral neuropathy (TIPN) symptoms and function. The overall incidence, manifestations, characteristics, and mechanisms of CIPN are also discussed. While some studies in this narrative review demonstrated that exercise programs may have benefits on sensory and motor TIPN symptoms in some but not all patients, there are consistent benefits of improved QoL and physical function across most patients. This narrative review highlights the need for future research to confirm the effects of exercise for TIPN, with a focus on other important components, including the effect of exercise adherence, type, and supervision level.","PeriodicalId":93484,"journal":{"name":"Physiologia","volume":"49 12","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135430503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.3390/physiologia3040041
Maria D. Koskolou, Georgios Georgas, Anastasios Makris, Stylianos Kounalakis
Breath-hold diving has been traditionally practiced for professional and recreational reasons and has recently emerged as a competitive sport. The physiological response during breath-holding, also known as diving response, consists mainly of bradycardia and peripheral vasoconstriction. Elite apneists can suppress the urge to breathe, sustain greater arterial desaturation and develop pronounced bradycardia, thus accomplishing impressively long breath-hold times. This study explored physiological responses during static apnea and their association with apnea duration in breath-hold divers with high physiological adaptations acquired from long-term apnea training. Nine well-trained competitive divers held their breath for as long as possible while floating motionlessly in a swimming pool (26–27 °C), simulating an actual “static apnea competition”. Long apnea durations (302 ± 60 s) as well as severe oxygen desaturation (minSaO2 46 ± 11%) and bradycardia (minHR 49 ± 8 bpm) were achieved. Apnea duration was positively correlated with forced vital capacity (r = 0.771) and apnea duration until initiation of desaturation (r = 0.736) and negatively correlated with minSaO2 (r = −0.672) (p < 0.05). Moreover, minHR during apnea was correlated with pre-apneic hemoglobin concentration (r = 0.685) (p < 0.05). The prolonged apnea durations achieved by the well-trained divers in this study, while performing maximum immersed static apnea under competitive simulated conditions, were related to their high lung volumes and their delayed and profound O2 desaturation, whereas their bradycardic response was not a decisive factor.
{"title":"Physiological Responses during Prolonged Immersed Static Apnea in Well-Trained Apneists","authors":"Maria D. Koskolou, Georgios Georgas, Anastasios Makris, Stylianos Kounalakis","doi":"10.3390/physiologia3040041","DOIUrl":"https://doi.org/10.3390/physiologia3040041","url":null,"abstract":"Breath-hold diving has been traditionally practiced for professional and recreational reasons and has recently emerged as a competitive sport. The physiological response during breath-holding, also known as diving response, consists mainly of bradycardia and peripheral vasoconstriction. Elite apneists can suppress the urge to breathe, sustain greater arterial desaturation and develop pronounced bradycardia, thus accomplishing impressively long breath-hold times. This study explored physiological responses during static apnea and their association with apnea duration in breath-hold divers with high physiological adaptations acquired from long-term apnea training. Nine well-trained competitive divers held their breath for as long as possible while floating motionlessly in a swimming pool (26–27 °C), simulating an actual “static apnea competition”. Long apnea durations (302 ± 60 s) as well as severe oxygen desaturation (minSaO2 46 ± 11%) and bradycardia (minHR 49 ± 8 bpm) were achieved. Apnea duration was positively correlated with forced vital capacity (r = 0.771) and apnea duration until initiation of desaturation (r = 0.736) and negatively correlated with minSaO2 (r = −0.672) (p < 0.05). Moreover, minHR during apnea was correlated with pre-apneic hemoglobin concentration (r = 0.685) (p < 0.05). The prolonged apnea durations achieved by the well-trained divers in this study, while performing maximum immersed static apnea under competitive simulated conditions, were related to their high lung volumes and their delayed and profound O2 desaturation, whereas their bradycardic response was not a decisive factor.","PeriodicalId":93484,"journal":{"name":"Physiologia","volume":"55 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135370814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-11-01DOI: 10.3390/physiologia3040040
Christopher R. Harnish, Thomas C. Swensen, Deborah King
Background: The purpose of this study is to ascertain the reliability of two 15-s sprint cycling tests in men and women to estimate the maximum lactate accumulation rate (VLamax). Methods: Eighteen men and twelve women completed two sprint sessions over 1 week. A 10 min warm-up preceded the obtaining of a 3 µL blood lactate (BLC) sample, after which a 15 s sprint was completed; cyclists then rested passively while multiple lactate samples were taken until the levels peaked. Trial differences and reliability across trials were analyzed using a paired-sample t-test, Pearson’s correlation, Intraclass correlation (ICC), and Bland–Altman analysis with α = 0.05 for all tests; data are reported as mean ± sd. Results: Power (W) was similar across trials (773.0 ± 143.5 vs. 758.2 ± 127.4; p = 0.333) and the coefficient of variation (CV) of 4.7%. VLamax (mM·L−1·s−1) was similar (0.673 ± 0.024 vs. 0.635 ± 0.237; p = 0.280), but only moderately reliable across trials with CV, ICC, and R values of 18.6%, 0.661, and 0.67, respectively. Pre-BLC and peak BLC CV were 45.6 and 23.3%, respectively. Conclusions: A 15 s VLamax cycling sprint is moderately reliable, possibly affected both by the lactate measurement and other variables used in the calculation. More research may offer ways to improve reliability.
{"title":"Reliability of the 15-s Maximal Lactate Accumulation Rate (VLamax) Test for Cycling","authors":"Christopher R. Harnish, Thomas C. Swensen, Deborah King","doi":"10.3390/physiologia3040040","DOIUrl":"https://doi.org/10.3390/physiologia3040040","url":null,"abstract":"Background: The purpose of this study is to ascertain the reliability of two 15-s sprint cycling tests in men and women to estimate the maximum lactate accumulation rate (VLamax). Methods: Eighteen men and twelve women completed two sprint sessions over 1 week. A 10 min warm-up preceded the obtaining of a 3 µL blood lactate (BLC) sample, after which a 15 s sprint was completed; cyclists then rested passively while multiple lactate samples were taken until the levels peaked. Trial differences and reliability across trials were analyzed using a paired-sample t-test, Pearson’s correlation, Intraclass correlation (ICC), and Bland–Altman analysis with α = 0.05 for all tests; data are reported as mean ± sd. Results: Power (W) was similar across trials (773.0 ± 143.5 vs. 758.2 ± 127.4; p = 0.333) and the coefficient of variation (CV) of 4.7%. VLamax (mM·L−1·s−1) was similar (0.673 ± 0.024 vs. 0.635 ± 0.237; p = 0.280), but only moderately reliable across trials with CV, ICC, and R values of 18.6%, 0.661, and 0.67, respectively. Pre-BLC and peak BLC CV were 45.6 and 23.3%, respectively. Conclusions: A 15 s VLamax cycling sprint is moderately reliable, possibly affected both by the lactate measurement and other variables used in the calculation. More research may offer ways to improve reliability.","PeriodicalId":93484,"journal":{"name":"Physiologia","volume":"55 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135370967","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-25DOI: 10.3390/physiologia3040039
Jérôme Bernier Brillon, Matthieu Moingt, Marc Lucotte
Soybeans are vulnerable to drought and temperature increases potentially induced by climate change. Hydraulic dysfunction and stomatal closure to avoid excessive transpiration are the main problems caused by drought. The vulnerability of soybeans to drought will depend on the intensity and duration of water stress. The purpose of this study was to determine if the use of cover crops (CCs) can influence the gas exchange potential of glyphosate-tolerant soybeans when the vapor pressure deficit (Vpd) increases. This two-year study was conducted in an open experimental field comprising direct seeding plots with or without CCs. Stomatal conductance (Gs) was measured five times on the same identified leaves following glyphosate-based herbicide application. These leaves were then collected in order to observe the stomata and foliar traits with a scanning electron microscope. The Vpd was calculated concomitantly to Gs measurements at the leaf surface. The results suggest that the use of CCs promotes phenotypic change in soybean leaves (more elaborate venation and a higher abaxial stomatal density), which in turn may enhance their tolerance to drier conditions. In 2019, Gs could be up to 29% higher in plots with CCs compared to those without CCs with similar Vpd values. This study shows that the benefits of using CCs can be observed via the morphological development strategies of the crop plants and their higher tolerance to drought.
{"title":"Influence of No-Till System with or without Cover Crops on Stomata Sensitivity of Glyphosate-Tolerant Soybeans to Vapor Pressure Deficit","authors":"Jérôme Bernier Brillon, Matthieu Moingt, Marc Lucotte","doi":"10.3390/physiologia3040039","DOIUrl":"https://doi.org/10.3390/physiologia3040039","url":null,"abstract":"Soybeans are vulnerable to drought and temperature increases potentially induced by climate change. Hydraulic dysfunction and stomatal closure to avoid excessive transpiration are the main problems caused by drought. The vulnerability of soybeans to drought will depend on the intensity and duration of water stress. The purpose of this study was to determine if the use of cover crops (CCs) can influence the gas exchange potential of glyphosate-tolerant soybeans when the vapor pressure deficit (Vpd) increases. This two-year study was conducted in an open experimental field comprising direct seeding plots with or without CCs. Stomatal conductance (Gs) was measured five times on the same identified leaves following glyphosate-based herbicide application. These leaves were then collected in order to observe the stomata and foliar traits with a scanning electron microscope. The Vpd was calculated concomitantly to Gs measurements at the leaf surface. The results suggest that the use of CCs promotes phenotypic change in soybean leaves (more elaborate venation and a higher abaxial stomatal density), which in turn may enhance their tolerance to drier conditions. In 2019, Gs could be up to 29% higher in plots with CCs compared to those without CCs with similar Vpd values. This study shows that the benefits of using CCs can be observed via the morphological development strategies of the crop plants and their higher tolerance to drought.","PeriodicalId":93484,"journal":{"name":"Physiologia","volume":"33 6","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135111345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-17DOI: 10.3390/physiologia3040038
Tomas J. Chapman-Lopez, James Kyle Taylor, Ricardo Torres, Dylan Wilburn, LesLee K. Funderburk, Dale C. Allison, Jeffrey S. Forsse
This study examined the effects of two different acute bouts of treadmill running (e.g., steady-state moderate-intensity exercise (SSE) and high-intensity interval exercise (HIIE)) on adipokine (e.g., adiponectin, leptin, and omentin) concentrations in individuals with moderate stages of chronic kidney disease (CKD). Fourteen participants (8 females and 6 males) (age 58.7 ± 9.7, height (cm) 168.5 ± 9.7, weight (kg) 83.5 ± 18.2) were classified as having moderate stages of CKD (stages G3a and G3b; estimated glomerular filtration rate (eGFR) between 59 and 30 mL/min/1.73 m2). Participants completed 30 min of either SSE at 65% oxygen consumption reserve (VO2R) or HIIE for 3 min at a 90% VO2R separated by 2 min of slow walking (20% VO2R) in a randomized, crossover design on a treadmill. Venous blood samples were obtained at baseline, 1 h, and 24 h post exercise. Data were analyzed using a two by three repeated measures ANOVA (p < 0.05). There were no significant differences in adiponectin (p < 0.353), leptin (p < 0.084), and omentin (p < 0.235) concentrations between SSE and HIIE. Similarly, no significant differences were seen between the sampled time points for either aerobic exercise condition. In conclusion, this study demonstrated there were no changes in adiponectin, leptin, or omentin concentrations when performing an acute bout of HIIE or SSE for 30 min, at 1 or 24 h post exercise. Future studies should seek to either increase the duration of the exercise bout or identify different adipokines to examine for patients experiencing moderate stages of CKD.
{"title":"The Effects of Acute Bouts of Aerobic Exercise on Adipokine Concentrations in Individuals with Moderate Stages of Chronic Kidney Disease","authors":"Tomas J. Chapman-Lopez, James Kyle Taylor, Ricardo Torres, Dylan Wilburn, LesLee K. Funderburk, Dale C. Allison, Jeffrey S. Forsse","doi":"10.3390/physiologia3040038","DOIUrl":"https://doi.org/10.3390/physiologia3040038","url":null,"abstract":"This study examined the effects of two different acute bouts of treadmill running (e.g., steady-state moderate-intensity exercise (SSE) and high-intensity interval exercise (HIIE)) on adipokine (e.g., adiponectin, leptin, and omentin) concentrations in individuals with moderate stages of chronic kidney disease (CKD). Fourteen participants (8 females and 6 males) (age 58.7 ± 9.7, height (cm) 168.5 ± 9.7, weight (kg) 83.5 ± 18.2) were classified as having moderate stages of CKD (stages G3a and G3b; estimated glomerular filtration rate (eGFR) between 59 and 30 mL/min/1.73 m2). Participants completed 30 min of either SSE at 65% oxygen consumption reserve (VO2R) or HIIE for 3 min at a 90% VO2R separated by 2 min of slow walking (20% VO2R) in a randomized, crossover design on a treadmill. Venous blood samples were obtained at baseline, 1 h, and 24 h post exercise. Data were analyzed using a two by three repeated measures ANOVA (p < 0.05). There were no significant differences in adiponectin (p < 0.353), leptin (p < 0.084), and omentin (p < 0.235) concentrations between SSE and HIIE. Similarly, no significant differences were seen between the sampled time points for either aerobic exercise condition. In conclusion, this study demonstrated there were no changes in adiponectin, leptin, or omentin concentrations when performing an acute bout of HIIE or SSE for 30 min, at 1 or 24 h post exercise. Future studies should seek to either increase the duration of the exercise bout or identify different adipokines to examine for patients experiencing moderate stages of CKD.","PeriodicalId":93484,"journal":{"name":"Physiologia","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135943947","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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