Metabolic adjustments to breath holding in higher vertebrates

1989 ◽  
Vol 67 (12) ◽  
pp. 3024-3031 ◽  
Author(s):  
P. J. Butler
Keyword(s):  
Marine Mammals ◽  
Lactate Production ◽  
Weddell Seal ◽  
Specific Dynamic Action ◽  
The Body ◽  
Breath Holding ◽  
Reduced Body ◽  
Key Factor ◽  
Reduced Rate ◽  
Anaerobic Production

There is substantial behavioural and physiological evidence to suggest that most feeding dives by aquatic birds and mammals are aerobic in nature, with no net production of lactate. Any increase in lactate production is matched by increased removal. This does not mean, however, that there are no cardiovascular adjustments associated with such dives. Nonactive parts of the body (including the large pectoral muscles in diving ducks) may be hypoperfused and consume oxygen at a reduced rate. For example, in marine mammals, such as the Weddell seal, reduced perfusion of the gut during a feeding period (which can last for up to 12 h) would reduce the energy expenditure associated with the digestion and assimilation of food (specific dynamic action). Reperfusion during the nonfeeding period would contribute to an unusually high "resting" oxygen uptake. Although some tissues in seals at least can tolerate periods of ischaemia, there is no evidence to suggest that enhanced anaerobic production of ATP is a key factor in the survival of marine mammals during unusually long periods underwater. There may, in fact, be an overall reduction in the ATP requirements of certain tissues, possibly as a result of a reduction in the permeability of cell membranes to some ions, but most certainly as a result of reduced body temperature. During relatively long dives, lactate production eventually exceeds its rate of removal and it accumulates. Precisely what occurs in the muscles is not known. One suggestion is that periods of vasoconstriction are interrupted by vasodilatation, when the oxygen stores are replaced.

scholarly journals Exploring the Effects of Problematic Internet Use on Adolescent Sleep: A Systematic Review

2021 ◽  
Vol 18 (2) ◽  
pp. 760
Author(s):  
Ioulia Kokka ◽  
Iraklis Mourikis ◽  
Nicolas C. Nicolaides ◽  
Christina Darviri ◽  
George P. Chrousos ◽  
...  
Keyword(s):  
Internet Use ◽  
Educational Interventions ◽  
The Body ◽  
Problematic Internet Use ◽  
Affecting Factors ◽  
Physical And Mental Health ◽  
Adolescent Sleep ◽  
Key Factor ◽  
Parental Educational Level ◽  
The Impact

Adolescent suse internet via several devices to gather information or communicate. Sleep, as a key factor of adolescents’ development, contributes to their physical and mental health. Over the past decades insufficient sleep among adolescents has been wide spread, and one of its attributing factors is the increased availability of technology. This review aims to investigate the body of evidence regarding the impact of problematic internet use on adolescent sleep. Extensive search of databases was performed according to PRISMA guidelines for studies published within the last decade, regarding subjects aged 10–19. The final step of the search yielded 12 original studies. The quality of extracted data was evaluated with the AXIS tool, in order to estimate the risk of bias. All studies showed a negative correlation between adolescent sleep and problematic internet use. It was found to affect sleep quality and quantity and provoke insomnia symptoms. Interestingly, adolescent’s sex, parental educational level, type of family and use for leisure or academic reasons appeared as affecting factors of the problematic internet use-sleep relationship. Problematic internet use has several effects on adolescents’ sleep. Results of relevant studies should be embedded in educational interventions addressed to adolescents as well as parents, to eliminate the negative outcomes of problematic internet use on sleep and adolescence’s health in general.

scholarly journals Cleaner birds: an overview for the Neotropics

2010 ◽  
Vol 10 (4) ◽  
pp. 195-203 ◽  
Author(s):  
Ivan Sazima ◽  
Cristina Sazima
Keyword(s):  
Marine Mammals ◽  
Bird Species ◽  
The Body ◽  
Domestic Dog ◽  
Large Herbivores ◽  
Broad Category ◽  
Organic Debris ◽  
Marine Reptiles ◽  
Black Vulture ◽  
Do So

Several bird species feed on a variety of external parasites and epibionts, organic debris, dead and wounded tissue, clots and blood, and secretions from the body of other vertebrates (hosts or clients). We present an overview of so called cleaner birds from the Neotropics based on field records, literature, and photo survey. We found that 33 bird species in 16 families practice cleaning even if some of them do so very occasionally. The birds range from the Galápagos ground finch Geospiza fuliginosa to the widespread black vulture Coragyps atratus. Clients mostly are large herbivores such as capybaras, deer, and livestock, but also include medium-sized herbivores such as iguanas and tortoises, and carnivores such as boobies and seals - a few bird species associate with these latter marine mammals. No carnivorous terrestrial mammal client is recorded to date except for a domestic dog, from whose hair black vultures picked organic debris. Some clients adopt particular inviting postures while being cleaned, whereas others are indifferent or even disturbed by the activity of cleaner birds. Capybaras, giant tortoises, and iguanas are among the inviting clients, whereas boobies try to dislodge the 'vampire' finch Geospiza difficilis. Most of the Neotropical cleaner birds may be lumped in one broad category (omnivores that dwell in open areas and associate with large to medium-sized herbivores). A second, restricted category accommodates some species from Patagonia and the Galápagos Islands (omnivores that dwell in open areas and associate with carnivorous marine mammals, or seabirds and marine reptiles). Two still more restricted categories accommodate the following: 1) forest-dwelling cleaner birds; and 2) marine coastal cleaners. Additional records of Neotropical cleaner birds will mostly fall in the broad category.

scholarly journals Regulation of glycogen phosphorylase and PDH during exercise in human skeletal muscle during hypoxia

2000 ◽  
Vol 278 (3) ◽  
pp. E522-E534 ◽  
Author(s):  
Michelle L. Parolin ◽  
Lawrence L. Spriet ◽  
Eric Hultman ◽  
Melanie G. Hollidge-Horvat ◽  
Norman L. Jones ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Glycogen Phosphorylase ◽  
Lactate Production ◽  
Muscle Metabolism ◽  
Lactate Accumulation ◽  
Pyruvate Oxidation ◽  
Reduced Rate ◽  
Rate Limiting ◽  
Muscle Biopsies ◽  
Elevated Lactate

The present study examined the acute effects of hypoxia on the regulation of skeletal muscle metabolism at rest and during 15 min of submaximal exercise. Subjects exercised on two occasions for 15 min at 55% of their normoxic maximal oxygen uptake while breathing 11% O2 (hypoxia) or room air (normoxia). Muscle biopsies were taken at rest and after 1 and 15 min of exercise. At rest, no effects on muscle metabolism were observed in response to hypoxia. In the 1st min of exercise, glycogenolysis was significantly greater in hypoxia compared with normoxia. This small difference in glycogenolysis was associated with a tendency toward a greater concentration of substrate, free Pi, in hypoxia compared with normoxia. Pyruvate dehydrogenase activity (PDHa) was lower in hypoxia at 1 min compared with normoxia, resulting in a reduced rate of pyruvate oxidation and a greater lactate accumulation. During the last 14 min of exercise, glycogenolysis was greater in hypoxia despite a lower mole fraction of phosphorylase a. The greater glycogenolytic rate was maintained posttransformationally through significantly higher free [AMP] and [Pi]. At the end of exercise, PDHawas greater in hypoxia compared with normoxia, contributing to a greater rate of pyruvate oxidation. Because of the higher glycogenolytic rate in hypoxia, the rate of pyruvate production continued to exceed the rate of pyruvate oxidation, resulting in significant lactate accumulation in hypoxia compared with no further lactate accumulation in normoxia. Hence, the elevated lactate production associated with hypoxia at the same absolute workload could in part be explained by the effects of hypoxia on the activities of the rate-limiting enzymes, phosphorylase and PDH, which regulate the rates of pyruvate production and pyruvate oxidation, respectively.

scholarly journals A Bayesian computational model reveals a failure to adapt interoceptive precision estimates across depression, anxiety, eating, and substance use disorders

2020 ◽  
Vol 16 (12) ◽  
pp. e1008484
Author(s):  
Ryan Smith ◽  
Rayus Kuplicki ◽  
Justin Feinstein ◽  
Katherine L. Forthman ◽  
Jennifer L. Stewart ◽  
...  
Keyword(s):  
Substance Use ◽  
Computational Model ◽  
Substance Use Disorders ◽  
The Body ◽  
Breath Holding ◽  
Healthy Individuals ◽  
Prior Beliefs ◽  
Future Studies ◽  
Psychiatric Conditions ◽  
Processing Mechanisms

Recent neurocomputational theories have hypothesized that abnormalities in prior beliefs and/or the precision-weighting of afferent interoceptive signals may facilitate the transdiagnostic emergence of psychopathology. Specifically, it has been suggested that, in certain psychiatric disorders, interoceptive processing mechanisms either over-weight prior beliefs or under-weight signals from the viscera (or both), leading to a failure to accurately update beliefs about the body. However, this has not been directly tested empirically. To evaluate the potential roles of prior beliefs and interoceptive precision in this context, we fit a Bayesian computational model to behavior in a transdiagnostic patient sample during an interoceptive awareness (heartbeat tapping) task. Modelling revealed that, during an interoceptive perturbation condition (inspiratory breath-holding during heartbeat tapping), healthy individuals (N = 52) assigned greater precision to ascending cardiac signals than individuals with symptoms of anxiety (N = 15), depression (N = 69), co-morbid depression/anxiety (N = 153), substance use disorders (N = 131), and eating disorders (N = 14)–who failed to increase their precision estimates from resting levels. In contrast, we did not find strong evidence for differences in prior beliefs. These results provide the first empirical computational modeling evidence of a selective dysfunction in adaptive interoceptive processing in psychiatric conditions, and lay the groundwork for future studies examining how reduced interoceptive precision influences visceral regulation and interoceptively-guided decision-making.

scholarly journals Excretion of Heavy Metals and Glyphosate in Urine and Hair Before and After Long-Term Fasting in Humans

2021 ◽  
Vol 8 ◽  
Author(s):  
Franziska Grundler ◽  
Gilles-Eric Séralini ◽  
Robin Mesnage ◽  
Vincent Peynet ◽  
Françoise Wilhelmi de Toledo
Keyword(s):  
Heavy Metals ◽  
Environmental Pollutants ◽  
Dietary Exposure ◽  
The Body ◽  
Health Concern ◽  
Obese People ◽  
Clinical Trial Registration ◽  
Reduced Body ◽  
Before And After

Background: Dietary exposure to environmental pollutants in humans is an important public health concern. While long-term fasting interrupts the dietary exposure to these substances, fat mobilization as an energy source may also release bioaccumulated substances. This was, to our knowledge, only investigated in obese people decades ago. This study explored the effects of 10-days fasting on the excretion of heavy metals and glyphosate.Methods: Urinary levels of arsenic, chromium, cobalt, lead, nickel, mercury and glyphosate were measured before and after 10 fasting days in 109 healthy subjects. Additionally, hair analysis was done before and ten weeks after fasting in 22 subjects.Results: Fasting caused a decrease in body weight, and in urinary arsenic (by 72%) and nickel (by 15%) concentrations. A decrease in lead hair concentrations (by 30%) was documented. Urinary mercury levels were unchanged for chromium, cobalt and glyphosate, which were undetectable in most of the subjects. Additionally, fatigue, sleep disorders, headache and hunger were reduced. Body discomfort symptoms diminished four weeks after food reintroduction.Conclusions: The results of this study provide the first insights into the changes in heavy metal excretion caused by long-term fasting. Further studies focusing on the kinetics of efflux between different compartments of the body are needed.Clinical Trial Registration:https://www.drks.de/drks_web/navigate.do?navigationId=trial.HTML&TRIAL_ID=DRKS00016657, identifier: DRKS00016657.

Interactive Agencies and Digitalization Readiness

2017 ◽  
Vol 8 (4) ◽  
pp. 48-64
Author(s):  
Leila Behboudi
Keyword(s):  
Organizational Culture ◽  
The Body ◽  
Critical Factors ◽  
Key Factors ◽  
Technology Infrastructure ◽  
Factors Affecting ◽  
Global Trend ◽  
Key Factor ◽  
Financial Infrastructure ◽  
Management Participation

This study presents primarily factors affecting interactive agencies in Iran. There is a kind of unwillingness among Iranian ad agencies to execute online ad campaign in compare to the global trend and the advantage of use of online ad makes it imperative to find the key factors affecting interactive agencies behavior. Accordingly, the body of literature was analyzed and eight critical factors including “Management participation,” “Organizational culture,” “Size of the organization,” “The level of organization technology,” “Communication infrastructure,” “Financial infrastructure,” “Technology infrastructure” and “Electronic readiness,” were extracted. The expert questionnaire was designed to validate the gathered factors. By analyzing 294 questionnaires, the type of management was found as key factor in adopting online ad campaign execution.

scholarly journals Lactate as substrate for mitochondrial respiration in alveolar epithelial type II cells

2015 ◽  
Vol 308 (9) ◽  
pp. L953-L961 ◽  
Author(s):  
Robyn G. Lottes ◽  
Danforth A. Newton ◽  
Demetri D. Spyropoulos ◽  
John E. Baatz
Keyword(s):  
Mitochondrial Respiration ◽  
Lactate Production ◽  
The Body ◽  
Monocarboxylate Transporter ◽  
Dependent Manner ◽  
Type Ii ◽  
Alveolar Epithelial ◽  
Atp Generation ◽  
Lactate Consumption ◽  
Healthy Lung

Because of the many energy-demanding functions they perform and their physical location in the lung, alveolar epithelial type II (ATII) cells have a rapid cellular metabolism and the potential to influence substrate availability and bioenergetics both locally in the lung and throughout the body. A thorough understanding of ATII cell metabolic function in the healthy lung is necessary for determining how metabolic changes may contribute to pulmonary disease pathogenesis; however, lung metabolism is poorly understood at the cellular level. Here, we examine lactate utilization by primary ATII cells and the ATII model cell line, MLE-15, and link lactate consumption directly to mitochondrial ATP generation. ATII cells cultured in lactate undergo mitochondrial respiration at near-maximal levels, two times the rates of those grown in glucose, and oxygen consumption under these conditions is directly linked to mitochondrial ATP generation. When both lactate and glucose are available as metabolic substrate, the presence of lactate alters glucose metabolism in ATII to favor reduced glycolytic function in a dose-dependent manner, suggesting that lactate is used in addition to glucose when both substrates are available. Lactate use by ATII mitochondria is dependent on monocarboxylate transporter (MCT)-mediated import, and ATII cells express MCT1, the isoform that mediates lactate import by cells in other lactate-consuming tissues. The balance of lactate production and consumption may play an important role in the maintenance of healthy lung homeostasis, whereas disruption of lactate consumption by factors that impair mitochondrial metabolism, such as hypoxia, may contribute to lactic acid build-up in disease.

Hydration status of Greco-Roman wrestlers in an authentic precompetition situation

2013 ◽  
Vol 38 (6) ◽  
pp. 621-625 ◽  
Author(s):  
Vahur Ööpik ◽  
Saima Timpmann ◽  
Andres Burk ◽  
Innar Hannus
Keyword(s):  
Specific Gravity ◽  
Body Mass ◽  
Urine Osmolality ◽  
Mass Gain ◽  
The Body ◽  
Urine Specific Gravity ◽  
Hydration Status ◽  
Greco Roman ◽  
Reduced Body ◽  
Body Mass Gain

We assessed the urinary indexes of hydration status of Greco-Roman wrestlers in an authentic precompetition situation at the time of official weigh-in (OWI). A total of 51 of 89 wrestlers competing in the Estonian Championship in 2009 donated a urine sample. Questionnaire responses revealed that 27 wrestlers (body mass losers (BMLs)) reduced body mass before the competition, whereas 24 wrestlers (those who do not lose body mass (n-BMLs)) did not. In 42 wrestlers, values of urine specific gravity ≥1.020 and urine osmolality ≥700 mOsmol·kg−1 revealed a hypohydrated status. The prevalence of hypohydration in the BMLs (96%) was higher than in the n-BMLs (67%) (χ2 = 7.68; p < 0.05). The prevalence of serious hypohydration (urine specific gravity >1.030) was 5.3 times greater (χ2 = 8.32; p < 0.05) in the BMLs than in the n-BMLs. In the BMLs, the extent of body mass gain during the 16-h recovery (2.5 ± 1.2 kg) was associated (r = 0.764; p < 0.05) with self-reported precompetition body mass loss (4.3 ± 2.0 kg) and exceeded the body mass gain observed in the n-BMLs (0.7 ± 1.2 kg; p < 0.05). We conclude that hypohydration is prevalent among Greco-Roman wrestlers at the time of OWI. The prevalence of hypohydration and serious hypohydration is especially high among wrestlers who are accustomed to reducing body mass before competition. These results suggest that an effective rehydration strategy is needed for Olympic-style wrestlers, and that changes in wrestling rules should be considered to reduce the prevalence of harmful body mass management behaviours.

scholarly journals Follistatin Regulates Germ Cell Nest Breakdown and Primordial Follicle Formation

Endocrinology ◽  
2010 ◽  
Vol 152 (2) ◽  
pp. 697-706 ◽  
Author(s):  
Fuminori Kimura ◽  
Lara M. Bonomi ◽  
Alan L. Schneyer
Keyword(s):  
Germ Cell ◽  
Germ Cells ◽  
Ovarian Function ◽  
Primordial Follicle ◽  
Biochemical Properties ◽  
The Body ◽  
Protein Isoforms ◽  
Primordial Follicles ◽  
Reduced Rate ◽  
Regulatory Functions

Abstract Follistatin (FST) is an antagonist of activin and related TGFβ superfamily members that has important reproductive actions as well as critical regulatory functions in other tissues and systems. FST is produced as three protein isoforms that differ in their biochemical properties and in their localization within the body. We created FST288-only mice that only express the short FST288 isoform and previously reported that females are subfertile, but have an excess of primordial follicles on postnatal day (PND) 8.5 that undergo accelerated demise in adults. We have now examined germ cell nest breakdown and primordial follicle formation in the critical PND 0.5–8.5 period to test the hypothesis that the excess primordial follicles derive from increased proliferation and decreased apoptosis during germ cell nest breakdown. Using double immunofluorescence microscopy we found that there is virtually no germ cell proliferation after birth in wild-type or FST288-only females. However, the entire process of germ cell nest breakdown was extended in time (through at least PND 8.5) and apoptosis was significantly reduced in FST288-only females. In addition, FST288-only females are born with more germ cells within the nests. Thus, the excess primordial follicles in FST288-only mice derive from a greater number of germ cells at birth as well as a reduced rate of apoptosis during nest breakdown. These results also demonstrate that FST is critical for normal regulation of germ cell nest breakdown and that loss of the FST303 and/or FST315 isoforms leads to excess primordial follicles with accelerated demise, resulting in premature cessation of ovarian function.

The metabolic rate and thermal conductance of the eastern barred bandicoot (Perameles gunnii) at different ambient temperatures

2003 ◽  
Vol 51 (6) ◽  
pp. 603 ◽  
Author(s):  
M. P. Ikonomopoulou ◽  
R. W. Rose
Keyword(s):  
Oxygen Consumption ◽  
Body Temperature ◽  
Metabolic Rate ◽  
Thermal Conductance ◽  
The Body ◽  
High Metabolic Rate ◽  
Ambient Temperatures ◽  
Reduced Body ◽  
Thermoneutral Zone ◽  
Reproductive Females

We investigated the metabolic rate, thermoneutral zone and thermal conductance of the eastern barred bandicoot in Tasmania. Five adult eastern barred bandicoots (two males, three non-reproductive females) were tested at temperatures of 3, 10, 15, 20, 25, 30, 35 and 40°C. The thermoneutral zone was calculated from oxygen consumption and body temperature, measured during the daytime: their normal resting phase. It was found that the thermoneutral zone lies between 25°C and 30°C, with a minimum metabolic rate of 0.51 mL g–1 h–1 and body temperature of 35.8°C. At cooler ambient temperatures (3–20°C) the body temperature decreased to approximately 34.0°C while the metabolic rate increased from 0.7 to 1.3 mL g–1�h–1. At high temperatures (35°C and 40°C) both body temperature (36.9–38.7°C) and metabolic rate (1.0–1.5 mL g–1 h–1) rose. Thermal conductance was low below an ambient temperature of 30°C but increased significantly at higher temperatures. The low thermal conductance (due, in part, to good insulation, a reduced body temperature at lower ambient temperatures, combined with a relatively high metabolic rate) suggests that this species is well adapted to cooler environments but it could not thermoregulate easily at temperatures above 30°C.

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