Evaluation of efficacy and indications of surgical fixation for multiple rib fractures: a propensity-score matched analysis.

PURPOSE: The purpose of this study was to assess the effects of recent surgical rib fixation and establish its indications not only for flail chest but also for multiple rib fractures. METHODS: Between 2007 and 2015, 187 patients were diagnosed as having multiple rib fractures in our institution. After the propensity score matching was performed, ten patients who had performed surgical rib fixation and ten patients who had treated with non-operative management were included. Categorical variables were analyzed with Fischer's exact test and non-parametric numerical data were compared using the Mann-Whitney U test. Wilcoxon signed-rank test was performed for comparison of pre- and postoperative variables. All statistical data are presented as median (25-75 % interquartile range [IQR]) or number. RESULTS: The surgically treated patients extubated significantly earlier than non-operative management patients (5.5 [1-8] vs 9 [7-12] days: p = 0.019). The duration of continuous intravenous narcotic agents infusion days (4.5 [3-6] vs 12 [9-14] days: p = 0.002) and the duration of intensive care unit stay (6.5 [3-9] vs 12 [8-14] days: p = 0.008) were also significantly shorter in surgically treated patients. Under the same ventilating conditions, the postoperative values of tidal volume and respiratory rate improved significantly compared to those values measured just before the surgery. The incidence of pneumonia as a complication was significantly higher in non-operative management group (p = 0.05). CONCLUSIONS: From the viewpoints of early respiratory stabilization and intensive care unit disposition without any complications, surgical rib fixation is a sufficiently acceptable procedure not only for flail chest but also for repair of severe multiple rib fractures.

A convenient NMR method for in situ observation of aerobically cultured cells.

We observed P31-NMR signals of intracellular phosphorylated metabolites, i.e. ATP, NAD(H) and UDPG, in the aerobically cultured cells of AJ13375 (a derivative of E. coli K-12) without a cell culture circulating system, which needs much more cells. Each NMR spectrum of 40 ml cell-culture was obtained with a 25 mm Phi sample tube mini-fermenter equipped with a pH electrode and three supply routes for O2 gas, aqueous ammonia and glucose. Spectra were measured at 15-min intervals. When glucose in the culture medium was consumed, P31-NMR signals of ATP disappeared first and then those of ADP decreased to below the limit of detection. The intracellular concentration of ATP was estimated to be approximately 7 mM.

Construction of an L-isoleucine overproducing strain of Escherichia coli K-12.

The genes for a threonine deaminase that is resistant to feedback inhibition by L-isoleucine and for an active acetohydroxyacid synthase II were introduced by a plasmid into a L-threonine-producing recombinant strain of Escherichia coli K-12. Analysis of culture broth of the strain using 13C nuclear magnetic resonance suggested that alpha, beta-dihydroxy-beta-methylvalerate (DHMV) and alpha-keto-beta-methylvalerate (KMV), the third and the fourth intermediates in the L-isoleucine biosynthetic pathway from L-threonine, respectively, accumulated in the medium in amounts comparable to that of L-isoleucine. The ratio of accumulated L-isoleucine:DHMV:KMV were approximately 2:1:1. The concentration of accumulated L-isoleucine increased by twofold after the additional introduction of the genes for dihyroxyacid dehydratase (DH) and transaminase-B (TA-B), and the intermediates no longer accumulated. The resultant strain TVD5 accumulated 10 g/l of L-isoleucine from 40 g/l of glucose.

Structure determination of metabolites isolated from urine and bile after administration of AY4166, a novel D-phenylalanine-derivative hypoglycemic agent.

Molecular structures of 10 metabolites, which were isolated from urine (M1-M8) or bile (M9 and M10) after administration of AY4166 (N-(trans-4-isopropylcyclohexanecarbonyl)-D-phenylalanine), a novel amino acid derivative with hypoglycemic activity, have been elucidated by mass spectrometry and nuclear magnetic resonance. Four of these (M1, M2, M3 and M8) were determined to be hydroxyl derivatives of AY4166, two (M9 and M10) were carboxylate derivatives via oxidization of M2 and M3, three (M4, M5 and M6) were glucronic acid conjugates and the other (M7) was a dehydro derivative. The estimated structures for M1, M2, M3, M7, M8, M9 and M10 were confirmed by the coincidence of the retention time of HPLC, MS and 1H NMR spectra between the isolated metabolites and authentic synthesized substances. For three glucronic acid conjugates, M4, M5 and M6, structural confirmation was performed by a selective enzymatic digestion with beta-glucronidase. M1 and M2/3 were about 5-6 and 3 times less potent than AY4166, respectively, and M7 was almost as potent as AY4166.

The interaction of elderberry (Sambucus sieboldiana) bark lectin and sialyloligosaccharides as detected by 1H-NMR.

The interaction of Japanese elderberry bark lectin (Sambucus sieboldiana agglutinin, SSA) with carbohydrate was investigated by 1H-NMR. When a low affinity ligand, methyl beta-D-galactoside (beta MeGal), was mixed with SSA, each proton signal of beta MeGal was broadened. The signal of H-4 was markedly broad, while those of H-1, OCH3, and H-2 of beta MeGal were rather sharp. The specific broadening of Gal H-4 was more evident when SSA was mixed with methyl-beta-D-lactoside (beta MeLac). Position-dependent signal broadening suggests that beta MeGal binds to SSA such that H-4 is closely involved in the contact region, but H-1, OCH3, and H-2 are far from this region. In the case of a high affinity ligand, Neu5Ac(alpha 2-6)Gal(beta 1-4)Glc(= N6L), ligand signals of the SSA-N6L mixture did not change at all. But when a small amount of N6L was added to the SSA-beta MeGal mixture, the broad signals of bound beta MeGal became dramatically sharp. This indicates that the added N6L molecules liberated the bound beta MeGal from SSA. On the other hand, the sialyllactose with the alpha(2-3)-linkage(= N3L) could not substitute for bound beta MeGal because of its lower affinity. This demonstrates that the competitive binding experiment between two ligands is a useful technique to detect the interaction of lectins with high affinity ligands which could not be observed directly by NMR signal broadening and/or chemical shift change.

Hydrogen-deuterium exchange in the histidine residues of bovine alpha-lactalbumin.

The proton magnetic resonance spectrum of bovine alpha-lactalbumin has been observed, and three peaks assignable to the position-2 CH protons of the three histidine rpsidues (His 32, 68, and 107) of this protein have been subjected to detailed examination. The assignments of these peaks to His 32, 68, and 107 were made on the basis of the difference in their reactivities with iodoacetic acid. The rate constants of the hydrogen-deuterium exchange reactions were found to be 8.0 X 10(-5), 2.6 X 10(-4), and 8.0 X 10(-5) min-1, respectively, at pH 8.5 and at 35 degrees, while at 62 degrees all three were found to be 0.84 approximately 1.1 X 10(-2) min-1. On the basis of these data, it has been shown that, in the native form of this protein, His 68 is the most exposed to the solvent while His 32 and His 107 are buried slightly deeper in the surface of the molecule. The fluctuation amplitudes gamma, or the effective chances of His 32, 68, and 107 to be fully exposed to the solvent, were found to be 0.4, 1.3, and 0.4, respectively.