4 research outputs found
Successful recording perioperarive hemodynamic changes with the severe right diaphragmatic hernia
We experienced a case of severe congenital diaphragmatic hernia (CDH) with severe deleterious hypoxemia after birth in which we succeeded in saving the patient with radical surgery. Observation of the patient's detailed hemodynamics was possible for the entire perioperative period. The central venous pressure (CVP) was high according to the pressure in the liver. The CVP subsequently decreased after the operation, and the oxygen saturation increased. Therefore, the cardiac diastolic disorder improved. This case suggests that the diastolic dysfunction in severe CDH patients is worsen by compression from herniated visceral organs
Imidazole C‑2 Hydrogen/Deuterium Exchange Reaction at Histidine for Probing Protein Structure and Function with Matrix-Assisted Laser Desorption Ionization Mass Spectrometry
We present a mass spectrometric method
for analyzing protein structure
and function, based on the imidazole C-2 or histidine C<sup>ε1</sup> hydrogen/deuterium (H/D) exchange reaction, which is intrinsically
second-order with respect to the concentrations of the imidazolium
cation and OD<sup>–</sup> in D<sub>2</sub>O. The second-order
rate constant (<i>k</i><sub>2</sub>) of this reaction was
calculated from the pH dependency of the pseudo-first-order rate constant
(<i>k</i><sub>φ</sub>) obtained from the change in
average mass [Δ<i>M</i><sub>r</sub> (0 ≤ Δ<i>M</i><sub>r</sub> < 1)] of a peptide fragment containing
a defined histidine residue at incubation time (<i>t</i>) such that <i>k</i><sub>φ</sub> = −[lnÂ(1
– Δ<i>M</i><sub>r</sub>)]/<i>t</i>. We preferred using <i>k</i><sub>2</sub> rather than <i>k</i><sub>φ</sub> because <i>k</i><sub>2</sub><sup>max</sup> (maximal value
of <i>k</i><sub>2</sub>) was empirically related to p<i>K</i><sub>a</sub> as illustrated with a Brønsted plot [log <i>k</i><sub>2</sub><sup>max</sup> = −0.7p<i>K</i><sub>a</sub> + α (α
is an arbitrary constant)], so that we could analyze the effect of
structure on the H/D exchange rate in terms of logÂ(<i>k</i><sub>2</sub><sup>max</sup>/<i>k</i><sub>2</sub>) representing the deviation of <i>k</i><sub>2</sub> from <i>k</i><sub>2</sub><sup>max</sup>. In the catalytic site of bovine ribonuclease
A, His12 showed a change in logÂ(<i>k</i><sub>2</sub><sup>max</sup>/<i>k</i><sub>2</sub>) much larger than that of His119 upon binding with cytidine 3′-monophosphate,
as anticipated from the X-ray structures and the possible change in
solvent accessibility. However, we need to consider the hydrogen bonds
of the imidazole group with nondissociable groups to interpret an
extremely slow H/D exchange rate of His48 in a partially solvent-exposed
situation