Disease relevance of hydroxymethanone

• Dehydration of the resulting H2CO3 into CO2 and H2O is catalysed by carbonic anhydrase, which is present in surface cells in large amounts [1].
• Suppressing alkalosis with 5% ambient CO2 abolished seizures within 20 s [2].
• Acetogenesis from H2 plus CO2 by spirochetes from termite guts [3].
• Low-frequency positive-pressure ventilation with extracorporeal CO2 removal in severe acute respiratory failure [4].
• We propose that midbrain raphé neurons are sensors of blood CO2 that maintain pH homeostasis by inducing arousal, anxiety and changes in cerebrovascular tone in response to respiratory acidosis [5].

Psychiatry related information on hydroxymethanone

• The combination of reduction of sensitivity to CO2 and lower tissue PCO2 during REM sleep makes it likely that the output of the central chemoreceptors during this state is less than that during SWS and wakefulness [6].
• Patients with panic disorder may have hypersensitive CO2 receptors that, when triggered, evoke a subjective panic associated with an exaggerated ventilatory response and consequent hypocapnic alkalosis [7].
• Chemoreceptor sensitivity was assessed by using a rebreathing technique to measure the ventilatory response to CO2 in 14 medication-free patients with agoraphobia and panic attacks and 23 healthy subjects [8].
• Nuclear-localized mtDNA pseudogenes might explain a recent report describing a heteroplasmic mtDNA molecule containing five linked missense mutations dispersed over the contiguous mtDNA CO1 and CO2 genes in Alzheimer's disease (AD) patients [9].
• METHOD: Responses to hyperventilation and CO2 inhalation were compared across groups of patients with the four main DSM-IV specific phobia types, a group with panic disorder, and a group of comparison subjects with no anxiety disorder (N = 15 per group) [10].

High impact information on hydroxymethanone

• CO2 also prevented two long-term effects of hyperthermic seizures in the hippocampus: the upregulation of the I(h) current and the upregulation of CB1 receptor expression [2].
• The model predicts that fluxes of CO2 and energy are invariant of ecosystem biomass, but are strongly influenced by temperature, variation in cellular metabolism and rates of supply of limiting resources (water and/or nutrients) [11].
• We find that sea surface temperatures increased by 3.5-4.0 degrees C during the last two glacial-interglacial transitions, synchronous with the global increase in atmospheric CO2 and Antarctic warming, but the temperature increase occurred 2,000-3,000 years before the Northern Hemisphere ice sheets melted [12].
• Here we show that growth of an intact Populus deltoides plantation under increased CO2 (800 micromol x mol(-1) and 1,200 micromol x mol(-1)) reduced ecosystem isoprene production by 21% and 41%, while above-ground biomass accumulation was enhanced by 60% and 82%, respectively [13].
• Increased levels of CO2 can be found in all terrestrial ecosystems [14].

Chemical compound and disease context of hydroxymethanone

• PC were stimulated by hypoxia (10% O2/90% N2) (n = 6) and central chemoreceptors by hypercapnia (7% CO2/93% O2) (n = 6) [15].
• Total deficiency of band 3 also resulted in defective Cl-/HCO3- exchange, causing mild acidosis with decreases in the HCO3- concentration and total CO2 in the proband blood [16].
• Of the other patients, four panicked with sodium lactate, none with 5% CO2, and one with room air hyperventilation [7].
• Carbon dioxide was administered for 15 minutes to patients with panic disorders (5% CO2, n = 14) and healthy subjects (5% CO2, n = 11; 7.5% CO2, n = 8) [17].
• Cytoplasmic acidosis is accelerated in maize root tips that are either (i) deficient in alcohol dehydrogenase, so that lactic acid production continues throughout hypoxia, or (ii) exposed to external CO2 during hypoxia, or (iii) perfused slowly so that escape of CO2 produced during ethanolic fermentation is retarded [18].

Biological context of hydroxymethanone

• One implication of this limitation is that a larger iron supply to the region in glacial times could have stimulated algal photosynthesis, leading to lower concentrations of atmospheric CO2 [19].
• The increased CO2 enhanced plant nitrogen uptake, microbial biomass carbon, and available carbon for microbes [20].
• Although CO2-induced cerebral vasodilatation in wild-type mice is NO-dependent, in nNOS- mice this vasodilation is unaffected by NOS inhibitors [21].
• The magnitude of the direct radiative forcing from black carbon itself exceeds that due to CH4, suggesting that black carbon may be the second most important component of global warming after CO2 in terms of direct forcing [22].
• Here we present evidence that CO2 induces exocytosis by a cascade of events, the first step of which is cytoplasmic acidification [23].

Anatomical context of hydroxymethanone

• There are three reports of membranes with very low permeabilities to NH3 (refs 5-7), and none of membranes impermeable to CO2 [24].
• The importance of CO2 for Ca2+ uptake by some mitochondria [25].
• Here we show that serotonergic neurons in the midbrain of rats are also highly chemosensitive to small changes in CO2/pH and are closely associated with large penetrating arteries [5].
• Conclusions were: (a) hyperventilation in response to CO inhalation is not mediated by the carotid bodies; (b) the delayed hyperpnea in response to CO inhalation is primarily due to brain-cerebrospinal fluid acidosis; (c) mobilization of body CO2 stores due to the circulatory response to CO may obscure an initial depression of ventilation by CO [26].
• An animal model was developed to describe respiratory muscle work output, blood flow, and oxygen consumption during mechanical ventilation, resting spontaneous ventilation, and the increased unobstructed ventilatory efforts induced by CO2 rebreathing [27].

Associations of hydroxymethanone with other chemical compounds

• An abundant chloroplast protein is implicated in the assembly of the oligomeric enzyme ribulose bisphosphate carboxylase-oxygenase, which catalyses photosynthetic CO2-fixation in higher plants [28].
• Hydrogen escape after CH4 photolysis, therefore, causes a net gain of oxygen [CO2 + 2H2O --> CH4 + 2O2 --> CO2 + O2 + 4H(upward arrow space)] [29].
• In contrast, the maximal effect of insulin on glucose conversion to CO2 plus lipids was much greater in the adipocytes from females than males (increment over basal: 472 vs. 249 nmol/10(6) cells per 2 h) [30].
• There was no effect of bath sodium removal on cell pH in the absence of CO2/HCO3 [31].
• Bicarbonate permeability was estimated from the flux of total CO2 along known electrochemical gradients into bicarbonate-and chloride-free perfusion solution containing 10(-4) M acetazolamide [32].

Gene context of hydroxymethanone

• Arabidopsis HT1 kinase controls stomatal movements in response to CO2 [33].
• Arabidopsis T-DNA insertional knockout mutants show no GLYK activity and are not viable in normal air; however, they grow under elevated CO2, providing direct evidence of the obligatory nature of the ultimate step of the C2 cycle [34].
• Here, we present evidence that CA II in red cell lysates can be quantitated by measuring CO2 hydratase activity in the presence of inhibitors that selectively inhibit the activity of CA I to a much greater extent than that of CA II [35].
• Cytosolic malic enzyme catalyzes the NADP(+)-dependent oxidative decarboxylation of malate to pyruvate and CO2 [36].
• Nitrate reductase (NR), the first enzyme in the nitrate assimilation pathway, is regulated post-transcriptionally in response to light and CO2 [37].

Analytical, diagnostic and therapeutic context of hydroxymethanone

• Stomata form pores on leaf surfaces that regulate the uptake of CO2 for photosynthesis and the loss of water vapour during transpiration [38].
• The sheep had been cannulated for veno-venous extracorporeal perfusion so that CO2 could be infused into the peripheral venous blood through membrane lungs in the perfusion circuit [39].
• The sheep breathed room air through an endo-tracheal tube inserted through a tracheostomy, and samples of expired gas were collected for measurement of the rates of CO2 production and O2 consumption [39].
• We systematically studied the effect on pulmonary CO2 elimination (VCO2) of varying f (2-30 Hz) and VT (1-7 ml/kg) as well as lung volume (VL) in 13 anesthetized, paralyzed dogs in order to examine the contribution of those variables that are thought to be important in determining gas exchange by high frequency ventilation [40].
• Alterations of minute ventilation in the postoperative period produced by 3% CO2 did not influence the compensatory growth process, nor did administration of cyclophosphamide [41].

References