Disease relevance of hydrogen

• This study was designed to establish the relationship between urinary pCO2 and systemic blood pCO2 during acute hypercapnia and to investigate the significance of this relationship to collecting duct hydrogen ion (H+) secretion when the urine is acid and when it is highly alkaline [1].
• We determined the prevalence of lactase deficiency by analysis of respiratory hydrogen (H2) in 30 women with idiopathic postmenopausal osteoporosis and in 31 female control subjects without evidence of metabolic bone disease [2].
• BACKGROUND: Proton magnetic resonance spectroscopy (1H-MRS) and neuropsychological tests may be useful for monitoring the effectiveness of highly active antiretroviral therapy (HAART) in HIV-associated brain injury [3].
• METHODS: Proton magnetic resonance spectroscopy (MRS) at short-echo time (30 ms) was assessed in the frontal white matter, basal ganglia, and parietal cortex of 100 HIV patients [61 with AIDS dementia complex (ADC) and 39 neuroasymptomatic (NAS)] and 37 seronegative (SN) controls [4].
• CONCLUSIONS: Proton MRS has the potential to separate out a group of truly benign follicular neoplasms from follicular tumors (both follicular adenomas and follicular carcinomas) that have an atypical follicular pattern on cytologic examination [5].

Psychiatry related information on hydrogen

• BACKGROUND: Elevated brain Cho has been shown within the basal ganglia and frontal (i.e., orbitofrontal and cingulate) cortices in patients with mood disorders utilizing Proton Magnetic Resonance Spectroscopy (1H-MRS) [6].
• METHODS: Eighteen male patients with combat-related posttraumatic stress disorder (mean age 51.2 +/- 2.5 years) and 19 male control subjects (mean age 51.8 +/- 3.2 years) were studied using magnetic resonance imaging and Proton magnetic resonance spectroscopic imaging [7].
• DESIGN AND SUBJECTS: Proton magnetic resonance spectroscopy was used to compare 10 patients with dementia of the Alzheimer type and 8 age-matched patients with vascular dementia [8].
• CONCLUSION: Proton magnetic resonance spectroscopy may be useful in distinguishing between dementia of the Alzheimer type and vascular dementia [8].
• METHOD: Proton magnetic resonance spectroscopic imaging examinations were conducted in 25 males with Tourette's disorder (age 10.9 +/- 2.0 years) and 32 male comparison subjects (age 11.5 +/- 2.7 years) [9].

High impact information on hydrogen

• In May 1991, the Proton Radiation Oncology Group was formed to design, supervise, and coordinate clinical trials and to assist in data analysis [10].
• Hydrogen ion concentration in the mucus layer on top of acid-stimulated and -inhibited rat gastric mucosa [11].
• In histamine-stimulated tissues, the initial rise and subsequent rapid fall in potential difference, rise in resistance, and inhibition of hydrogen ion (H+) secretion induced by SAN did not occur with ASAN unless hydrolysis of ASAN produced a SAN of greater than 3 mM [12].
• Use of hydrogen gas (H2) analysis to assess intestinal absorption. Studies in normal rats and in rats infected with the nematode, Nippostrongylus brasiliensis [13].
• A dye dilution technique was used to determine simultaneously gastric fractional emptying, hydrogen ion (H+) output, fluid output, and H+ concentration of the gastric juice [14].

Chemical compound and disease context of hydrogen

• CONCLUSIONS: Proton MR spectroscopy is a useful diagnostic method for determining the proliferative or malignant potential of meningiomas according to the Cho/Cr ratio [15].
• The effect of 600 mg of cimetidine given twice daily on 24-hour intragastric hydrogen ion (H+) concentration was compared with that of the standard regimen of 300 mg of cimetidine given four times daily in six patients with asymptomatic duodenal ulcer [16].
• Background: Proton pump inhibitor-amoxicillin-metronidazole is recommended as second-line Helicobacter pylori therapy in Japan. The authors assessed the efficacy and safety of second-line eradication using the H(2)-receptor antagonist famotidine as a substitute for proton pump inhibitor [17].
• These results confirmed that populations were separately adapted to H(+) or Al(3+) toxicity and this was dependent upon the soil characteristics at their site of collection [18].
• On the conformational dependence of the proton chemical shifts in nucleosides and nucleotides. II. Proton shifts in the ribose ring of purine nucleosides as a function of the torsion angle about the glycosyl bond [19].

Biological context of hydrogen

• These proteins have binuclear Cu active sites that are distant, that exhibit no exchange interaction, and that activate O(2) at a single Cu center to generate a reactive Cu(II)/O(2) species for H-atom abstraction from the C-H bond of substrates [20].
• Human plasminogen. Proton NMR studies on kringle 1 [21].
• Kinetics and Mechanism of Proton Transport across Membrane Nanopores [22].
• After the H-atom abstraction, a reasonable pathway for substrate hydroxylation involves a "water-assisted" direct OH transfer to the substrate radical, which generates a high-energy Cu(II)(M)-oxyl species [23].
• Metal-ligand charge-transfer-promoted photoelectronic Bergman cyclization of copper metalloenediynes: photochemical DNA cleavage via C-4' H-atom abstraction [24].

Anatomical context of hydrogen

• Elastic incoherent neutron scattering is dominated by H atom scattering, and to study the dynamics of a selected part of BR, fully deuterated purple membrane with BR containing H-retinal, H-tryptophan, and H-methionine was prepared biosynthetically in Halobacterium salinarum [25].
• The syn-Oriented 2-OH Provides a Favorable Proton Transfer Geometry in 1,2-Diol Monoester Aminolysis: Implications for the Ribosome Mechanism [26].
• OBJECTIVE: Proton magnetic resonance spectroscopy ((1)H-MRS) studies of medicated patients with schizophrenia suggest high choline levels in the caudate nucleus [27].
• Sodium/Proton exchanger 3 in the medulla oblongata and set point of breathing control [28].
• A photoelectric apparatus and H2 electrode were applied to a small region of the cerebral cortex (left ectosylvian gyrus) for simultaneous measurement of the regional CBF [29].

Associations of hydrogen with other chemical compounds

• The identification of the CN versus H atom exchange channel makes these reactions compelling candidates to synthesize unsaturated nitriles in solar system environments [30].
• Reduced Prefrontal Glutamate/Glutamine and {gamma}-Aminobutyric Acid Levels in Major Depression Determined Using Proton Magnetic Resonance Spectroscopy [31].
• While kinetic results suggest that the HO2 radical reacts with the double allylic H atom of the polyunsaturated fatty acids, thermodynamic approximations indicate that the reaction is exothermic by approximately 10 kcal/mol [32].
• Mechanism of action of ethanolamine ammonia-lyase, an adenosylcobalamin-dependent enzyme. Proton nuclear magnetic resonance studies of the binding of adenine nucleosides and substrate to ethanolamine ammonia-lyase [33].
• The Role of Invariant Amino Acid Residues at the Hydride Transfer Site of Proton-translocating Transhydrogenase [34].

Gene context of hydrogen

• Hydrogen ion block was independent of voltage with K(d) values of 149+/-17.9 nM [H(+)] ( n=6) and 5.76+/-1.23 nM [H(+)] ( n=7) for TASK-1 and -2, respectively [35].
• CAIX has a major role in regulating hydrogen ion (H+) flux and blockade of CAIX results in increased cell death under hypoxia, indicating that it is one mechanism of hypoxic adaptation [36].
• Reaction thermodynamics and potential energy surfaces are calculated using density functional methods to investigate possible reactive Cu/O(2) species for H-atom abstraction in peptidylglycine alpha-hydroxylating monooxygenase (PHM), which has a noncoupled binuclear Cu active site [23].
• METHODS: Proton MRS was serially used to measure brain metabolites in strokelike regions and in clinically uninvolved brain regions in a patient with MELAS [37].
• We propose that the metabolism-based inactivation of nNOS by AG, DAG, and NAA occurs through oxidative removal of the hydrazine group and the formation of a radical intermediate that forms stable products after H-atom abstraction or reacts with the heme prosthetic moiety and inactivates nNOS [38].

Analytical, diagnostic and therapeutic context of hydrogen

• Assessment of H2 clearance confirmed that overall hepatic microvascular perfusion was decreased [39].
• As a consequence of the alternate oxidation and subsequent H atom migration processes, the atomic wire oxidation is actually found to occur on the H-terminated Si(100) surface at low temperatures without desorbing H atoms, as observed in our scanning tunneling microscopy experiment [40].
• CONCLUSIONS: Proton magnetic resonance spectroscopy and short-latency evoked potentials are of great benefit in the prognostic evaluation after cardiopulmonary resuscitation [41].
• (ii) Proton NMR titrations with AMP and MgATP suggested that substrate binding affinities and substrate-induced conformational changes are nearly identical between WT and R138K [42].
• CONCLUSION: Proton MR spectra obtained in the liver of women with silicone gel-filled breast implants helped measure silicone exposure [43].

References