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https://www.readbyqxmd.com/read/28088370/predator-prey-interaction-between-muricid-gastropods-and-mussels-under-ocean-acidification
#1
X-Y Xu, K R Yip, P K S Shin, S G Cheung
Predation of the muricid gastropod Thais clavigera on two-sized groups of the mussel Brachidontes variabilis was studied under three pCO2 levels, 380, 950, and 1250μatm. At 950μatm pCO2 level, the prey handling time decreased significantly and large-sized B. variabilis were preferred by T. clavigera. However, the prey consumption rate was independent of pCO2 levels, although the prey searching time increased significantly at elevated pCO2. These findings indicated that the predator-prey interaction between T...
January 11, 2017: Marine Pollution Bulletin
https://www.readbyqxmd.com/read/28087725/neurodevelopmental-outcomes-of-extremely-low-birthweight-infants-randomised-to-different-pco2-targets-the-phelbi-follow-up-study
#2
Ulrich H Thome, Orsolya Genzel-Boroviczeny, Bettina Bohnhorst, Manuel Schmid, Hans Fuchs, Oliver Rohde, Stefan Avenarius, Hans-Georg Topf, Andrea Zimmermann, Dirk Faas, Katharina Timme, Barbara Kleinlein, Horst Buxmann, Wilfried Schenk, Hugo Segerer, Norbert Teig, Annett Bläser, Roland Hentschel, Matthias Heckmann, Rolf Schlösser, Jochen Peters, Rainer Rossi, Wolfgang Rascher, Ralf Böttger, Jürgen Seidenberg, Gesine Hansen, Maria Zernickel, Harald Bode, Jens Dreyhaupt, Rainer Muche, Helmut D Hummler
BACKGROUND: Tolerating higher partial pressures of carbon dioxide (PCO2) in mechanically ventilated extremely low birthweight infants to reduce ventilator-induced lung injury may have long-term neurodevelopmental side effects. This study analyses the results of neurodevelopmental follow-up of infants enrolled in a randomised multicentre trial. METHODS: Infants (n=359) between 400 and 1000 g birth weight and 23 0/7-28 6/7 weeks gestational age who required endotracheal intubation and mechanical ventilation within 24 hours of birth were randomly assigned to high PCO2 or to a control group with mildly elevated PCO2 targets...
January 13, 2017: Archives of Disease in Childhood. Fetal and Neonatal Edition
https://www.readbyqxmd.com/read/28087656/conspecific-aggregations-mitigate-the-effects-of-ocean-acidification-on-calcification-of-the-coral-pocillopora-verrucosa
#3
Nicolas R Evensen, Peter J Edmunds
In densely populated communities, such as coral reefs, organisms can modify the physical and chemical environment for neighbouring individuals. We tested the hypothesis that colony density (12 colonies each placed∼0.5 cm apart versus∼8 cm apart) can modulate the physiological response (measured through rates of calcification, photosynthesis, and respiration in the light and dark) of the coral Pocillopora verrucosa to pCO2 treatments (∼ 400 µatm and∼1200 µatm) by altering the seawater flow regimes experienced by colonies placed in aggregations within a flume at a single flow speed...
January 13, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28081236/a-key-marine-diazotroph-in-a-changing-ocean-the-interacting-effects-of-temperature-co2-and-light-on-the-growth-of-trichodesmium-erythraeum-ims101
#4
Tobias G Boatman, Tracy Lawson, Richard J Geider
Trichodesmium is a globally important marine diazotroph that accounts for approximately 60 - 80% of marine biological N2 fixation and as such plays a key role in marine N and C cycles. We undertook a comprehensive assessment of how the growth rate of Trichodesmium erythraeum IMS101 was directly affected by the combined interactions of temperature, pCO2 and light intensity. Our key findings were: low pCO2 affected the lower temperature tolerance limit (Tmin) but had no effect on the optimum temperature (Topt) at which growth was maximal or the maximum temperature tolerance limit (Tmax); low pCO2 had a greater effect on the thermal niche width than low-light; the effect of pCO2 on growth rate was more pronounced at suboptimal temperatures than at supraoptimal temperatures; temperature and light had a stronger effect on the photosynthetic efficiency (Fv/Fm) than did CO2; and at Topt, the maximum growth rate increased with increasing CO2, but the initial slope of the growth-irradiance curve was not affected by CO2...
2017: PloS One
https://www.readbyqxmd.com/read/28073937/activity-of-tachykinin1-expressing-pet1-raphe-neurons-modulates-the-drive-to-breathe
#5
Morgan L Hennessy, Andrea Corcoran, Rachael D Brust, Eugene E Nattie, Susan Dymecki
: Homeostatic control of breathing, heart rate, and body temperature relies on circuits within the brainstem modulated by the neurotransmitter serotonin (5-HT). Mounting evidence points to specialized neuronal subtypes within the 5-HT system, which have borne out in functional studies, including the modulation of distinct facets of homeostatic control. These functional differences, read out at the organismal level, are likely subserved by differences among 5-HT neuron subtypes at the cellular and molecular levels, including differences in the capacity to co-express other neurotransmitters such as glutamate, GABA, thyrotropin releasing hormone, and substance P encoded by the Tachykinin-1 (Tac1) gene...
January 10, 2017: Journal of Neuroscience: the Official Journal of the Society for Neuroscience
https://www.readbyqxmd.com/read/28063520/zeta-potential-of-artificial-and-natural-calcite-in-aqueous-solution
#6
REVIEW
Dawoud Al Mahrouqi, Jan Vinogradov, Matthew D Jackson
Despite the broad range of interest and applications, controls on calcite surface charge in aqueous solution, especially at conditions relevant to natural systems, remain poorly understood. The primary data source to understand calcite surface charge comprises measurements of zeta potential. Here we collate and review previous measurements of zeta potential on natural and artificial calcite and carbonate as a resource for future studies, compare and contrast the results of these studies to determine key controls on zeta potential and where uncertainties remain, and report new measurements of zeta potential relevant to natural subsurface systems...
December 26, 2016: Advances in Colloid and Interface Science
https://www.readbyqxmd.com/read/28062941/the-effects-of-ph-and-pco2-on-photosynthesis-and-respiration-in-the-diatom-thalassiosira-weissflogii
#7
Johanna A L Goldman, Michael L Bender, François M M Morel
The response of marine phytoplankton to the ongoing increase in atmospheric pCO2 reflects the consequences of both increased CO2 concentration and decreased pH in surface seawater. In the model diatom Thalassiosira weissflogii, we explored the effects of varying pCO2 and pH, independently and in concert, on photosynthesis and respiration by incubating samples in water enriched in H2(18)O. In long-term experiments (~6-h) at saturating light intensity, we observed no effects of pH or pCO2 on growth rate, photosynthesis or respiration...
January 6, 2017: Photosynthesis Research
https://www.readbyqxmd.com/read/28060323/a-model-to-simulate-clinically-relevant-hypoxia-in-humans
#8
Lars Eichhorn, Florian Kessler, Volker Böhnert, Felix Erdfelder, Anja Reckendorf, Rainer Meyer, Richard K Ellerkmann
In case of apnea, arterial partial pressure of oxygen (pO2) decreases, while partial pressure of carbon dioxide (pCO2) increases. To avoid damage to hypoxia sensitive organs such as the brain, compensatory circulatory mechanisms help to maintain an adequate oxygen supply. This is mainly achieved by increased cerebral blood flow. Intermittent hypoxia is a commonly seen phenomenon in patients with obstructive sleep apnea. Acute airway obstruction can also result in hypoxia and hypercapnia. Until now, no adequate model has been established to simulate these dynamics in humans...
December 22, 2016: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28056071/species-specific-responses-of-juvenile-rockfish-to-elevated-pco2-from-behavior-to-genomics
#9
Scott L Hamilton, Cheryl A Logan, Hamilton W Fennie, Susan M Sogard, James P Barry, April D Makukhov, Lauren R Tobosa, Kirsten Boyer, Christopher F Lovera, Giacomo Bernardi
In the California Current ecosystem, global climate change is predicted to trigger large-scale changes in ocean chemistry within this century. Ocean acidification-which occurs when increased levels of atmospheric CO2 dissolve into the ocean-is one of the biggest potential threats to marine life. In a coastal upwelling system, we compared the effects of chronic exposure to low pH (elevated pCO2) at four treatment levels (i.e., pCO2 = ambient [500], moderate [750], high [1900], and extreme [2800 μatm]) on behavior, physiology, and patterns of gene expression in white muscle tissue of juvenile rockfish (genus Sebastes), integrating responses from the transcriptome to the whole organism level...
2017: PloS One
https://www.readbyqxmd.com/read/28054631/co2-induced-ph-reduction-increases-physiological-toxicity-of-nano-tio2-in-the-mussel-mytilus-coruscus
#10
Menghong Hu, Daohui Lin, Yueyong Shang, Yi Hu, Weiqun Lu, Xizhi Huang, Ke Ning, Yimin Chen, Youji Wang
The increasing usage of nanoparticles has caused their considerable release into the aquatic environment. Meanwhile, anthropogenic CO2 emissions have caused a reduction of seawater pH. However, their combined effects on marine species have not been experimentally evaluated. This study estimated the physiological toxicity of nano-TiO2 in the mussel Mytilus coruscus under high pCO2 (2500-2600 μatm). We found that respiration rate (RR), food absorption efficiency (AE), clearance rate (CR), scope for growth (SFG) and O:N ratio were significantly reduced by nano-TiO2, whereas faecal organic weight rate and ammonia excretion rate (ER) were increased under nano-TiO2 conditions...
January 5, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28043369/impact-of-acute-metabolic-acidosis-on-the-acid-base-balance-in-follicular-fluid-and-blood-in-dairy-cattle
#11
E Indrova, R Dolezel, J Novakova-Mala, A Pechova, M Zavadilova, S Cech
Acid-base balance is one of the most vigorously regulated variables of the body, including genital organs. Subacute ruminal acidosis is a common disturbance in dairy cows that disturbs several biochemical indices in the blood, cerebrospinal fluid, and urine. The possible negative effects of metabolic acidosis on the follicular fluid (FF) composition and, subsequently, on oocyte quality, are not fully elucidated. This study aimed to evaluate the changes in acid-base balance (ABB) in FF and blood during acute metabolic acidosis in dairy heifers...
February 2017: Theriogenology
https://www.readbyqxmd.com/read/28040384/circulatory-collapse-right-ventricular-dilatation-and-alveolar-dead-space-a-triad-for-the-rapid-diagnosis-of-massive-pulmonary-embolism
#12
Raúl J Gazmuri, Dimple J Patel, Rom Stevens, Shani Smith
A triad of circulatory collapse, right ventricular dilatation, and large alveolar dead space is proposed for the rapid diagnosis and treatment of massive pulmonary embolism. A 17year-old female on oral contraceptives collapsed at home becoming incoherent with shallow breathing. Paramedics initiated mechanical chest compression and transported the patient to our emergency department, arriving minimally responsive with undetectable blood pressure but having positive corneal reflexes and bradycardia with wide QRS...
December 16, 2016: American Journal of Emergency Medicine
https://www.readbyqxmd.com/read/28029292/ability-of-clinicopathologic-variables-and-clinical-examination-findings-to-predict-race-elimination-in-endurance-horses
#13
C Langdon Fielding, Chloe A Meier, Greg K Fellers, K Gary Magdesian
OBJECTIVE To compare results of point-of-care laboratory testing with standard veterinary clinical examination findings at a single time point during endurance competition to identify horses at risk for elimination. ANIMALS 101 endurance horses participating in the 2013 Western States 160-km (100-mile) endurance ride. PROCEDURES At the 58-km checkpoint, blood samples were collected from all horses. Samples were analyzed for pH, Pco2, base excess, anion gap, PCV, and whole blood concentrations of sodium, potassium, chloride, total carbon dioxide, BUN, glucose, and bicarbonate...
January 2017: American Journal of Veterinary Research
https://www.readbyqxmd.com/read/28019019/two-southern-ocean-diatoms-are-more-sensitive-to-ocean-acidification-and-changes-in-irradiance-than-the-prymnesiophyte-phaeocystis-antarctica
#14
Scarlett Trimborn, Silke Thoms, Tina Brenneis, Jasmin Pascale Heiden, Sara Beszteri, Kai Bischof
To better understand the impact of ocean acidification (OA) and changes in light availability on Southern Ocean phytoplankton physiology, we investigated the effects of pCO2 (380 and 800 µatm) in combination with low and high irradiance (20 or 50 and 200 µmol photons m(-2) s(-1) ) on growth, particulate organic carbon (POC) fixation and photophysiology in the three ecologically relevant species Chaetoceros debilis, Fragilariopsis kerguelensis and Phaeocystis antarctica. Irrespective of the light scenario, neither growth nor POC per cell was stimulated by OA in any of the tested species and the two diatoms even displayed negative responses in growth (e...
December 25, 2016: Physiologia Plantarum
https://www.readbyqxmd.com/read/28018656/european-sea-bass-show-behavioural-resilience-to-near-future-ocean-acidification
#15
M Duteil, E C Pope, A Pérez-Escudero, G G de Polavieja, I Fürtbauer, M R Brown, A J King
Ocean acidification (OA)-caused by rising concentrations of carbon dioxide (CO2)-is thought to be a major threat to marine ecosystems and has been shown to induce behavioural alterations in fish. Here we show behavioural resilience to near-future OA in a commercially important and migratory marine finfish, the Sea bass (Dicentrarchus labrax). Sea bass were raised from eggs at 19°C in ambient or near-future OA (1000 µatm pCO2) conditions and n = 270 fish were observed 59-68 days post-hatch using automated tracking from video...
November 2016: Royal Society Open Science
https://www.readbyqxmd.com/read/28017745/negative-pressure-hydrocephalus-a-case-report-on-successful-treatment-under-intracranial-pressure-monitoring-with-bilateral-ventriculoperitoneal-shunts
#16
Sajan Pandey, Yi Jin, Liang Gao, Cheng Chen Zhou, Da Ming Cui
Negative pressure hydrocephalus (NegPH), a very rare condition of unknown etiology and optimal treatment, usually presents post neurosurgery with clinical and imaging features of hydrocephalus but with negative cerebrospinal fluid pressure. We here describe a NegPH case of -3 mmHg ICP, that was successfully treated to achieve +5mmHg under continues intracranial pressure monitoring with horizontal positioning; head down and legs elevated to 10-15(o); neck wrapping for controlled venous drainage; chest and abdomen bandage; infusion of 5% dextrose fluid to lower plasma osmolarity (Na(+) 130-135 mmol/L); daily CSF drainage >200 ml; and arterial blood gas PCO2 >40mmHg...
December 22, 2016: World Neurosurgery
https://www.readbyqxmd.com/read/28012785/compensation-for-acid-base-disorders
#17
REVIEW
Chiara De Caro Carella, Helio Autran de Morais
Hydrogen concentration is a critical determinant of many physiologic functions and is tightly regulated. Any alteration in acid-base equilibrium sets into motion a compensatory response by either the lungs or the kidneys. The compensatory response attempts to return the ratio between Pco2 and [HCO3(-)] to normal and thereby minimize the pH change. A primary increase or decrease in one component is associated with a predictable compensatory change in the same direction in the other component, and the expected compensation can be estimated clinically in dogs and cats...
December 21, 2016: Veterinary Clinics of North America. Small Animal Practice
https://www.readbyqxmd.com/read/28011953/hyperventilation-assists-proarrhythmia-development-during-delayed-repolarization-in-clofilium-treated-anaesthetized-mechanically-ventilated-rabbits
#18
H Papp, A Sarusi, A S Farkas, H Takacs, P Kui, D Vincze, E Ivany, A Varro, J G Papp, T Forster, A Farkas
Hyperventilation reduces partial pressure of CO2 (PCO2) in the blood, which results in hypokalaemia. Hypokalaemia helps the development of the life-threatening torsades de pointes type ventricular arrhythmia (TdP) evoked by repolarization delaying drugs. This implies that hyperventilation may assist the development of proarrhythmic events. Therefore, this study experimentally investigated the effect of hyperventilation on proarrhythmia development during delayed repolarization. Phenylephrine (an α1-adrenoceptor agonist) and clofilium (as a representative repolarization delaying agent inhibiting the rapid component of the delayed rectifier potassium current, IKr) were administered intravenously to pentobarbital-anaesthetized, mechanically ventilated, open chest rabbits...
October 2016: Journal of Physiology and Pharmacology: An Official Journal of the Polish Physiological Society
https://www.readbyqxmd.com/read/28011948/molecular-hydrogen-affords-neuroprotection-in-a-translational-piglet-model-of-hypoxic-ischemic-encephalopathy
#19
J Nemeth, V Toth-Szuki, V Varga, V Kovacs, G Remzso, F Domoki
Hypoxic-ischemic encephalopathy (HIE) is the major consequence of perinatal asphyxia (PA) in term neonates. Although the newborn piglet is an accepted large animal PA/HIE model, there is no consensus on PA-induction methodology to produce clinically relevant HIE. We aimed to create and to characterize a novel PA model faithfully reproducing all features of asphyxiation including severe hypercapnia resulting in HIE, and to test whether H2 is neuroprotective in this model. Piglets were anaesthetised, artificially ventilated, and intensively monitored (electroencephalography, core temperature, O2 saturation, arterial blood pressure and blood gases)...
October 2016: Journal of Physiology and Pharmacology: An Official Journal of the Polish Physiological Society
https://www.readbyqxmd.com/read/28007620/postoperative-oxygen-therapy-in-patients-with-obstructive-sleep-apnea-a-randomized-controlled-trial
#20
Pu Liao, Jean Wong, Mandeep Singh, David T Wong, Sazzadul Islam, Maged Andrawes, Colin M Shapiro, David P White, Frances Chung, Frances Chung
BACKGROUND: Surgical patients with obstructive sleep apnea (OSA) are at increased risk for perioperative complications. Postoperative supplemental oxygen is commonly used but it may contribute to respiratory depression in OSA patients receiving opioids. The objective of the study is to investigate the effect of postoperative supplemental oxygen on SaO2, sleep respiratory events, and CO2 level in patients with untreated OSA. METHODS: Consented patients with an apnea hypopnea index (AHI) >5 events/h on a preoperative polysomnography were randomized (1:1) to oxygen (O2) or no oxygen (Control)...
December 19, 2016: Chest
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