Photoexcitation dynamics of p-nitroaniline and N,N-dimethyl-p-nitroaniline in 1-alkyl-3-methylimidazolium-cation based ionic liquids with different alkyl-chain lengths.

Photoexcitation dynamics of p-nitroaniline (pNA) and N,N-dimethyl-p-nitroaniline (DMpNA) in 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([Cnmim][NTf2]) with different alkyl chain lengths (from C2 to C12) was investigated using transient absorption spectroscopy. The internal conversion rate from the excited state to the ground state was estimated from bleach recovery around the ground state absorption centre, and the successive vibrational cooling rate in the ground state was estimated from the decay of the hot band observed at the red-edge of ground state absorption. The internal conversion rate slightly decreased with an increase in the alkyl-chain length of the cation, while the dependence of DMpNA was more significant than that of pNA. The extent of change was correlated with the change of the reaction free energy and solvent reorganization energy estimated from the absorption spectrum assuming that the internal conversion process is modelled by a back-electron-transfer process. The vibrational cooling rate estimated from the decay of hot-band absorption slightly decreased with an increase in the alkyl-chain length of the cation for both solutes. The hot-band decay of pNA was about 1.5-times faster than that of DMpNA, irrespective of the alkyl-chain length.

Polarity and Nonpolarity of Ionic Liquids Viewed from the Rotational Dynamics of Carbon Monoxide.

The rotational dynamics of carbon monoxide (CO) in a molten salt, ionic liquids (ILs), and alkanes were investigated by (17)O NMR T1 measurements using labeled C(17)O. The molten salt and the studied ILs have the bis(trifluoromethanesulfonyl)imide anion ([NTf2](-)) in common. In hexane near room temperature, the rotational relaxation times are close to the values predicted from the slip boundary condition in the Stokes-Einstein-Debye (SED) theory. However, in contradiction to the theoretical prediction, the rotational relaxation times decrease as the value of η/T increases, where η and T are the viscosity and absolute temperature, respectively. In other alkanes and ILs used in this study, the rotational relaxation times are much faster than those predicted by SED, and show a unique dependence on the number of alkyl carbons. For the same value of η/T, the CO rotational relaxation times in ILs composed of short-alkyl-chain-length imidazolium cations (1-ethyl-3-methylimidazolium and 1-butyl-3-methylimidazolium) are close to those for a molten salt (Cs[NTf2]). On the other hand, the rotational relaxation times in ILs composed of long-chain-length imidazolium (1-methyl-3-octylimidazolium) and phosphonium (tributylmethylphosphonium and tetraoctylphosphonium) cations are much shorter than the SED predictions. This deviation from theory increases as the alkyl chain length increases. We also found that the rotational relaxation times in dodecane and squalane are similar to those in ILs with a similar number of alkyl carbons. These results are discussed in terms of heterogeneous solvation and in comparison with the translational diffusion of CO in ILs.

Universality of Viscosity Dependence of Translational Diffusion Coefficients of Carbon Monoxide, Diphenylacetylene, and Diphenylcyclopropenone in Ionic Liquids under Various Conditions.

Translational diffusion coefficients of diphenylcyclopropenone (DPCP), diphenylacetylene (DPA), and carbon monoxide (CO) in 1-butyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([BMIm][NTf2]) and 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide ([EMIm][NTf2]) were determined by the transient grating (TG) spectroscopy under pressure from 0.1 to 200 MPa at 298 K and from 298 to 373 K under 0.1 MPa. Diffusion coefficients of these molecules at high temperatures in tributylmethylphosphonium bis(trifluoromethanesulfonyl)imide ([P4441][NTf2]), and tetraoctylphosphonium bis(trifluoromethanesulfonyl)imide ([P8888][NTf2]), and also in the mixtures of [BMIm][NTf2], N-methyl-N-propylpiperidinium bis(trifluoromethanesulfonyl)imide ([Pp13][NTf2]), and trihexyltetradecylphosphonium bis(trifluoromethanesulfonyl)imide ([P66614][NTf2]) with ethanol or chloroform have been determined. Diffusion coefficients except in ILs of phosphonium cations were well scaled by the power law of T/η, i.e., (T/η)(P), where T and η are the absolute temperature and the viscosity, irrespective of the solvent species, pressure and temperature, and the compositions of mixtures. The values of the exponent P were smaller for the smaller size of the molecules. On the other hand, the diffusion coefficients in ILs of phosphonium cations with longer alkyl chains were larger than the values expected from the correlation obtained by other ILs and conventional liquids. The deviation becomes larger with increasing the number of carbon atoms of alkyl-chain of cation, and with decreasing the molecular size of diffusing molecules. The molecular size dependence of the diffusion coefficient was correlated by the ratio of the volume of the solute to that of the solvent as demonstrated by the preceding work (Kaintz et al., J. Phys. Chem. B 2013 , 117 , 11697 ). Diffusion coefficients have been well correlated with the power laws of both T/η and the relative volume of the solute to the solvent.

5-Hydroxytryptamine-induced outward currents mediated via 5-HT(1A) receptors in neurons of the rat dorsolateral septal nucleus.

Effects of 5-hydroxytryptamine (5-HT) on neurons of the rat dorsolateral septal nucleus (DLSN) were examined by intracellular and whole-cell patch-clamp recording techniques. An outward current was induced by 5-HT (1-100 microM) in a concentration-dependent manner. The EC(50) for 5-HT was 4.8 microM. Also, 8-OH-DPAT (10-100 microM) produced the outward current an EC(50) of 17 microM. Amplitudes of the outward currents produced by 5-HT (100 microM) and 8-OH-DPAT (100 microM) were 117+/-4 (n=6) and 58+/-8 pA (n=6), respectively. Fluvoxamine (200 nM), a specific serotonin re-uptake inhibitor, enhanced the 5-HT (1 microM)-induced outward current: the EC(50) for 5-HT was 0.5 microM in the presence of fluvoxamine (200 nM). L-694247 (100 microM) and CP 93129 (100 microM) also produced outward currents with amplitudes of 33+/-3 (n=4) and 18+/-5 pA (n=4), respectively in DLSN neurons. DOI (100 microM) and RS 67333 (100 microM) did not produce outward currents. NAN-190 shifted, in a parallel manner, the concentration-response relationship of 5-HT to the right. The Lineweaver-Burk plot of the concentration-response curve showed that NAN-190 depressed the 5-HT-induced current in a competitive manner. The current-voltage relationship indicates that the 5-HT-induced current reversed polarity at a potential close to the equilibrium potential of K(+). Ba(2+) (100 microM-1 mM) partially depressed the outward current produced by 5-HT. These results suggest that 5-HT induces multiple K(+) currents via 5-HT(1A) receptors in DLSN neurons.

Clinical application of cardiac output during ramp exercise calculated using the Fick equation--comparison with the 2-stage bicycle ergometer exercise protocol in the supine position.

The purpose of this study was to clarify whether the direct Fick method is applicable to the measurement of cardiac output (Q) during ramp exercise. Twelve patients with chronic health failure underwent both a ramp exercise test and a steady-state exercise test. Oxygen intake (VO2), arterial oxygen saturation and mixed venous oxygen saturation were continuously measured using a pulse oximeter and a fiberoptic catheter, and the arteriovenous oxygen difference (a-v O2 diff) and Q were calculated. Both VO2 and a-v O2 diff were significantly lower in the ramp protocol than in the steady-state protocol when they were compared at the same workload. However, the VO2 vs Q relationship and the VO2 vs a-v O2 diff relationship were very similar in the 2 protocols. The difference between Q measured during steady-state exercise and Q calculated at the matched VO2 during ramp exercise was small (3.7 +/- 7.0% and 5.6 +/- 6.6%). The results indicate that, clinically, Q measured by the direct Fick method with simultaneous measurement of VO2 and a-v O2 diff during ramp exercise is a good substitute for the true Q measured by the steady-state protocol. We conclude that Fick Q is applicable to ramp exercise.

Dependence of peak oxygen uptake on oxygen transport capacity in chronic heart failure: comparison of graded protocol and fixed protocol.

Oxygen transport capacity is the most important determinant of maximum oxygen uptake (V(O2) max) in healthy subjects, however, its role is controversial in patients with chronic heart failure (CHF). The aim of this study was to clarify whether the oxygen transport capacity is an actual determinant of exercise capacity in CHF patients. Thirteen CHF patients underwent two maximum exercise tests, i.e., a graded protocol test and a fixed protocol test, measuring expiratory gases, leg blood flow (LBF), and arterial and venous blood gases. The workload of the fixed protocol was set to exceed the peak workload obtained by the graded protocol. Exercise with the fixed protocol caused significantly larger peak V(O2) compared to the graded protocol (813+/-194 to 971+/-203 ml/min, P<0.001). Peak LBF increased by 17%, while the peak leg arterio-venous oxygen difference increased by 5% from the graded protocol to the fixed protocol. The linear correlation between leg venous partial oxygen pressure and peak V(O2) was more clearly manifested in the fixed protocol (r=0.60, P<0.05) than in the graded protocol (r=0.47, NS). In conclusion, the exercise with graded protocol did not always conduct the upper limit of oxygen demand/supply relationship in CHF patients, whereas, the fixed protocol with a larger workload produced larger peak V(O2) and manifested the mechanism to limit V(O2) by oxygen transport capacity.

Separation of naphthalene and flavone derivatives by micellar electrokinetic chromatography with double- and triple-chain surfactants.

Three surfactants, p-bis(2-dodecyloxymethyl-3-oxa-6-sodiosulfonatohexyloxy)benz ene (BDSB) having two sulfonate groups and two lipophilic chains, disodium 10-dodecanoyl-5,15-bis(dodecyloxymethyl)-10-aza-4,7,13,16-tetra oxa-1,19-nonadecanedisulfonate (DDBTN) having two sulfonate groups and three lipophilic chains and disodium 4,11-bis(dodecyloxymethyl)-3,6,9,12-tetraoxa-1,14-tetrade canedionate (DBTT) having two carboxylate groups and two lipophilic chains, were used in micellar electrokinetic chromatography (MEKC). Eight naphthalene derivatives were baseline separated at 10 mM BDSB or 5 mM DBTT, and five flavone derivatives at 5 mM BDSB, DDBTN or DBTT. The elution order of the naphthalene derivatives in MEKC with BDSB was identical with that with DDBTN. However, this elution order was different from that found with DBTT. In the case of the flavone derivatives, BDSB, DDBTN and DBTT produced the identical elution order. These double- and triple-chain surfactants exhibited different selectivity when compared with widely used sodium dodecyl sulfate.

Comparison of results of intracoronary implantation of the Plamaz-Schatz stent with conventional balloon angioplasty in chronic total coronary arterial occlusion.

We compared angiographic and clinical outcomes after successful revascularization of chronic total coronary arterial occlusion with the placement of the Palmaz-Schatz stent (43 patients) and conventional balloon angioplasty (53 patients). After the procedure, the coronary stent led to a greater minimal lumen diameter than conventional balloon angioplasty (2.6 vs 1.7 mm, p < 0.001), resulting in a smaller residual stenosis (6.5% vs 36.7%, p < 0.001). At 6-month follow-up, there was no significant difference in late loss between the groups, resulting in a larger minimal lumen diameter at follow-up in the stent group (1.8 vs 1.1 mm, p < 0.001). The incidence of restenosis was lower in the stent group (27.9% vs 56.6%, p < 0.005). The frequency of the combination of myocardial infarction and coronary artery bypass graft surgery tended to be less in the stent group (2.3% vs 11.3%, P = 0.09). Placement of the Palmaz-Schatz stent improved left ventricular ejection fraction by 26% in patients who had reduced left ventricular function (p < 0.05), but conventional balloon angioplasty did not. Thus, placement of the Palmaz-Schatz stent provided a wider lumen than did conventional balloon angioplasty and, therefore, reduced the incidence of restenosis in chronic total coronary arterial occlusion. The lower restenosis rate of coronary stenting would be beneficial for long-term clinical outcome in patients with chronic total occlusion.

The role of cardiac output response in blood flow distribution during exercise in patients with chronic heart failure.

The relationship between blood flow in the working leg and cardiac output (Q) response was determined for patients with chronic heart failure. The ratio of leg blood flow (LBF) to Q (LBF/Q) at the same workload during submaximal exercise was significantly different in three groups of patients classified by peak cardiac index: it was 0.22 +/- 0.08 in the 'satisfactory' Q group vs 0.33 +/- 0.09 in the moderate Q group, and 0.38 +/- 0.08 in the poor Q group (P < 0.01) in the first stage of exercise. delta LBF/delta Q, the slope of change in leg blood flow to Q from rest to peak exercise, was significantly larger in the poor Q group than in the satisfactory Q group (P < 0.01). The intergroup arteriovenous oxygen difference (AVO2D) in organs other than the leg was large, while that in the working leg was small. Leg vascular resistance at submaximal workload was similar in the three groups, but vascular resistance in other organs was significantly higher in the poor Q group than in the satisfactory Q group (P < 0.001). These findings suggested that metabolic vasodilating stimuli in the working leg attenuated excessive vasoconstriction and caused a shift in blood flow from other organs to the working leg under conditions of severely reduced Q response.

Labeling of free carboxyl groups.

The latest trends in the labeling of free carboxyl groups for high-performance liquid chromatography are reviewed. The labeling reagents for fluorescence detection are mainly discussed according to their reaction type (or functional group). Attention is also paid to the reagents used for ultraviolet detection and for enantiomeric separation. The reactivity and sensitivity of the reagents used for the labeling of carboxylic acids are described.

Lactate threshold is not an onset of insufficient oxygen supply to the working muscle in patients with chronic heart failure.

It has been argued that the lactate threshold (LT) serves as an index to reflect circulatory insufficiency in transporting oxygen during submaximal exercise in patients with chronic heart failure (CHF). We examined whether or not the LT was related to an insufficient oxygen supply in patients with CHF. Sixty-nine patients were divided by NYHA classification. All underwent invasive cardiopulmonary exercise testing. The rate of increase in oxygen delivery (O2D) versus VO2 (delta O2D/delta VO2) was significantly lowered when work rate exceeded LT, that is, 1.32 +/- 0.35 to 1.05 +/- 0.37 (p < 0.01), 1.22 +/- 0.40 to 0.98 +/- 0.40 (p < 0.05), and 1.04 +/- 0.26 to 0.78 +/- 0.39 (p < 0.05) in NYHA classes I, II, and III, respectively. However, the rate of increase in leg O2D versus leg VO2 (delta LO2D/delta LVO2) did not change, that is, 1.25 +/- 0.20 to 1.29 +/- 0.20 (NS), 1.27 +/- 0.23 to 1.21 +/- 0.28 (NS), and 1.19 +/- 0.24 to 1.15 +/- 0.17 (NS) in classes I, II, and III, respectively. Leg venous PO2 was significantly different among three groups, that is, 23.7 +/- 3.4 mmHg, 23.2 +/- 2.8 mmHg, and 20.1 +/- 2.3 mmHg (p < 0.001), respectively. Thus, the oxygen supply to the working muscle did not become insufficient when work rate exceeded LT, and the LT occurred at different levels of leg PO2. It was concluded that the LT was not a result of anaerobiosis in patients with CHF.

Prognostic significance of atrial fibrillation in dilated cardiomyopathy.

We evaluated the relation of atrial rhythm to a clinical course of treatment in 147 patients diagnosed with dilated cardiomyopathy (DCM). Thirty-six of the patients (24%) had either transient (9 patients) or persistent (27 patients) atrial fibrillation (AF). Compared with DCM patients with sinus rhythm (SR), the AF patients did not differ in age, left ventricular (LV) dimension, fractional shortening, or hemodynamic parameters, but the AF patients had slightly larger left atria. After a mean follow-up of 3.8 +/- 2.9 years, the NYHA functional classifications in the AF patients improved in 20 of the 36 (56%), whereas those of the SR patients improved in only 30 (27%) (p < 0.01). The actuarial 5-year survival rate was significantly better for AF patients than for SR patients (93% versus 68%, p < 0.05). LV function remained unchanged in SR patients but improved significantly in AF patients, particularly in patients with transient AF and with "rate-controlled" AF (those with a mean heart rate of less than 90 beats/min). This study suggests that atrial fibrillation may result in significant LV dysfunction, which is reversible in some cases once the arrhythmia is controlled. Aggressive antiarrhythmic therapy should be considered for patients initially diagnosed with dilated cardiomyopathy and atrial fibrillation.

[Applicability to exercise test of thermodilution technique for right ventricular ejection fraction].

To assess the reliability of right ventricular ejection fraction (RVEF) during exercise measured by thermodilution technique using a modified Swan-Gantz catheter with a fast-response thermister, we measured RVEF under several conditions in 19 patients with cardiac disease. Measurements were repeated 5 times in each condition, and average RVEF and coefficient of variation (CV) were evaluated. 1) Injectate volume did not affect RVEF and CV. 2) A reduction in RVEF occurred with the thermister moved from proximal portion to distal portion within the pulmonary artery. 3) There were no differences in measurements of RVEF and CV between those during spontaneous breathing and those during apnea. 4) Postural change from supine to sitting decreased RVEF (38 +/- 8 to 35 +/- 9%; p < 0.05) and increased CV (7 +/- 2 to 13 +/- 5%). 5) Exercise increased RVEF (35 +/- 9 to 37 +/- 10%; p < 0.05) but did not change CV (13 +/- 5 vs 13 +/- 5%) compared with rest in the sitting position. 6) Cardiac rhythm (sinus vs atrial fibrillation) did not affect CV. 7) Average value of RVEF and CV during exercise were not different among 3, 4, 5 times repeated measurements. We considered that thermodilution technique for RVEF was applicable to exercise test, and 3 measurements were enough to determine the average value of RVEF during exercise.

Short- and mid-term follow-up results after percutaneous transvenous mitral commissurotomy.

This study reports the clinical follow-up for 6 months of 52 patients who underwent percutaneous transvenous mitral commissurotomy (PTMC). PTMC resulted in an increase in mitral valve area from 1.1 +/- 0.3 to 1.7 +/- 0.4 cm2 (p < 0.0001), a decrease in mean left atrial pressure from 16 +/- 7 to 13 +/- 5 mmHg (p < 0.0001), and an increase in exercise time from 4.6 +/- 2.1 to 6.3 +/- 2.3 min (p < 0.0001). At 6 months follow-up, mitral valve area was unchanged (1.7 +/- 0.4 cm2). Of 52 patients, 33 showed clinical improvement and 19 had no clinical improvement after PTMC. Univariate analysis showed (1) younger age, (2) echocardiographic score of 8 or less, (3) existence of mitral regurgitation of less than grade 2 after PTMC, and (4) amelioration in left atrial dimension, mean pulmonary artery pressure and exercise time after PTMC as correlative factors for clinical improvement. In conclusion, PTMC was an effective procedure for mitral stenosis, especially in younger patients with an echocardiographic score of 8 or less. Change in left atrial dimension was a good indicator of the effectiveness of PTMC.

The distribution of the blood flow during exercise in chronic heart failure--compensatory mechanism to the decreased cardiac output.

To evaluate the blood flow distribution during exercise, 51 patients with chronic heart failure underwent ergometer exercise testing measuring cardiac output and leg blood flow. At the given workrate (10 watts and 25 watts) cardiac index (L/min/m2) was significantly lower in NYHA class III patients than class I patients (at 10 watts, 4.08 +/- 1.05 in class I, 4.01 +/- 1.29 in class II and 3.00 +/- 0.89 in class III, p less than 0.05; I vs III), while leg blood flow (L/min/m2) was similar among 3 groups (at 10 watts, 1.19 +/- 0.32, 1.29 +/- 0.25 and 1.16 +/- 0.29, ns). Consequently, residual blood flow (L/min/m2) was significantly lower in class III than class I (at 10 watts, 2.89 +/- .92 and 2.78 +/- 1.27 and 1.84 +/- 0.71, p less than 0.05: I vs III). The results at 25 watts were similar. Serum noradrenaline was significantly higher in class III patients than class I patients at both 10 and 25 watts. We concluded that in severe heart failure, agreater blood flow is distributed to the working leg muscle as compared with less severe heart failure. And such an increased distribution of blood flow to working leg plays a role to compensate an insufficient cardiac output response in patients with severe heart failure.

[Blood flow redistribution and exercise intolerance in chronic heart failure].

We examined blood flow redistribution during exercise and its significance on exercise intolerance in chronic heart failure. Sixty-three patients with chronic heart diseases underwent symptom-limited maximal multistage exercise using a supine ergometer. We measured oxygen intake (VO2) and cardiac index (CI) using Fick's principle and leg flow with the thermodilution method at rest and during exercise. Patients were categorized in 5 groups according to their VO2 max; i.e., control group (n = 12), having normal right-sided cardiac pressure during exercise; A group (n = 8), having an abnormal right-sided pressure elevation, but normal exercise tolerance VO2 max greater than 20 ml/min/kg; B group (n = 19) VO2 max 20-15; C group (n = 17) also 15-10; and D group (n = 7), VO2 less than 10 ml/min/kg. At maximal exercise, the CI max and leg flow max were similar between the control and A groups; whereas, they decreased in the order of groups B, C and D. The ratio of leg flow/CI increased by 5 times from rest to maximal exercise in all groups, although the values at rest and at maximal exercise were similar among all groups. The relationship between CI and leg flow during exercise was linear in each individual patient. The coefficient of this regression line was extremely high (r = 0.98 +/- 0.02). Therefore, we calculated each regression line, leg flow = (a).CI +/- (b), with the gradient (a) as an index of blood flow redistribution to working skeletal muscles.(ABSTRACT TRUNCATED AT 250 WORDS)

New ultraviolet labelling agents for high-performance liquid chromatographic determination of monocarboxylic acids.

New UV-labelling agents have been synthesized, which are designed to convert monocarboxylic acids into their highly UV-absorbing derivatives for enhancement of the sensitivities of UV detection in high-performance liquid chromatography. The reagents are p-nitrobenzyl, 3,5-dinitrobenzyl and 2-(phthalimino)ethyl p-toluenesulphonates. Each has been prepared by reaction of p-toluenesulphonyl chloride with p-nitrobenzyl alcohol, 3,5-dinitrobenzyl alcohol or N-(hydroxyethyl)phtalimide, respectively, in the presence of sodium hydroxide, and they are stable in the solid state for at least 6 months. Monocarboxylic acids were derivatized to their p-nitrobenzyl, 3,5-dinitrobenzyl or 2-(phthalimino)ethyl esters with each of the above reagents, respectively, then determined by high-performance liquid chromatography with UV detection. In the UV-labelling with each reagent, 18-crown-6 was used as the catalyst. The effects of the reaction solvent, reaction temperature and time and the concentrations of each reagent and the catalyst were also examined.