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At least 667 records · Page 37Linked to original sources
PubMed1995

[Estimation of respiratory functions by analysis of expired gas and blood gas during artificial ventilation and general anesthesia].

One-hundred and seven patients undergoing elective surgery were studied to analyze the correlations between preoperative spirometric values and respiratory parameters during general anesthesia. They were grouped according to 3 criterions; preoperative %VC of less than 80%, FEV1.0% of less than 70%, V50/V25 exceeding 4.0. Following the induction of general anesthesia and of mechanical ventilation, expiratory flow (VE), FECO2, PaCO2 and PaO2 were measured to calculate respiratory parameters including VCO2-SR, VD/VT-Bohr, VD/VT-physiological (phys), a-ETDCO2, Volume Pressure Index (VPI) and A-aDO2. Six respiratory parameters were compared between the groups, and correlations between preoperative spirometric values were studied. Those with lower %VC had higher values in VCO2-SR and in VPI, and those with lower FEV1.0% had higher values in VCO2-SR, in VD/VT-phys and in a-ETDCO2. Significant correlations were also observed between these parameters. Preoperative V50/V25 and A-aDO2 during general anesthesia did not correlate with any of the parameters studied. We conclude that VCO2-SR, VD/VT-phys, a-ETDCO2 and VPI during general anesthesia are useful to detect the patients with restrictive and/or obstructive lung dysfunction, although they are not sensitive enough to detect those with small airway disease.

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PubMed2007

Observation of an unusually facile fragmentation pathway of gas-phase peptide ions: a study on the gas-phase fragmentation mechanism and energetics of tryptic peptides modified with 4-sulfophenyl isothiocyanate (SPITC) and 4-chlorosulfophenyl isocyanate (SPC) and their 18-crown-6 complexes.

Various peptide modifications have been explored recently to facilitate the acquisition of sequence information. N-terminal sulfonation is an interesting modification because it allows unambiguous de novo sequencing of peptides, especially in conjunction with MALDI-PSD-TOF analysis; such modified peptide ions undergo fragmentation at energies lower than those required conventionally for unmodified peptide ions. In this study, we systematically investigated the fragmentation mechanisms of N-terminal sulfonated peptide ions prepared using two different N-terminal sulfonation reagents: 4-sulfophenyl isothiocyanate (SPITC) and 4-chlorosulfophenyl isocyanate (SPC). Collision-induced dissociation (CID) of the SPC-modified peptide ions produced a set of y-series ions that were more evenly distributed relative to those observed for the SPITC-modified peptides; y(n-1) ion peaks were consistently and significantly larger than the signals of the other y-ions. We experimentally investigated the differences between the dissociation energies of the SPITC- and SPC-modified peptide ions by comparing the MS/MS spectra of the complexes formed between the crown ether 18-crown-6 (CE) and the modified peptides. Upon CID, the complexes formed between 18-crown-6 ether and the protonated amino groups of C-terminal lysine residues underwent either peptide backbone fragmentation or complex dissociation. Although the crown ether complexes of the unmodified ([M + CE + 2H]2+) and SPC-modified ([M* + CE + 2H]2+) peptides underwent predominantly noncovalent complex dissociation upon CID, the low-energy dissociations of the crown ether complexes of the SPITC-modified peptides ([M' + CE + 2H]2+) unexpectedly resulted in peptide backbone fragmentations, along with a degree of complex dissociation. We performed quantum mechanical calculations to address the energetics of fragmentations observed for the modified peptides.

Benzenesulfonates↗