Chemiluminescence of a cyclometallated iridium(III) complex and its application in the detection of cysteine.

Chemiluminescence (CL) of a cyclometallated iridium (III) complex {tris[1-(2,6-dimethylphenoxy)-4-(4-chlorophenyl)phthalazine]iridium(III)} in the presence of potassium permanganate and oxalic acid is reported for the first time. Cysteine exhibits sufficient enhancing effect on the CL generated from the cyclometallated iridium(III) complex, which make it possible for the sensitive detection of cysteine using a flow-injection-chemiluminescence (FI-CL) method. The optimum conditions for the chemiluminescence emission were investigated. Under the optimal condition, the linear range for the determination of cysteine was 1.0 × 10(-9) -5.0 × 10(-6) mol/L with a detection limit of 6.9 × 10(-10) mol/L. A relative standard deviation of 1.6% was obtained for eight replicate determinations. The mechanisms of CL are proposed and the emitting species was identified as the metal-to-ligand charge-transfer (MLCT) excited states of the iridium complex.

Enhancing and inhibiting effects of benzenediols on chemiluminescence of a novel cyclometallated iridium(III) complex.

A novel chemiluminescence (CL) system, including the cyclometallated iridium(III) complex {tris[1-(2,6-dimethylphenoxy)-4-(4-chlorophenyl)phthalazine]iridium}, potassium permanganate and oxalic acid, is proposed for the determination of benzenediols. This method is based on the fact that hydroquinone and catechol exhibited an inhibiting effect, while resorcinol exhibited an enhancing effect on CL intensity. The optimum conditions for CL emission were investigated. Under optimal conditions, the detection limits of hydroquinone, catechol and resorcinol were 6.4 × 10(-8), 2.7 × 10(-9) and 8.1 × 10(-7) mol/L, respectively. The method has been successfully applied to the determination of benzenediols in different types of water sample. The luminophors of the CL systems were all identified as the metal-ligand charge-transfer (MLCT) excited state of the iridium complex.

[Value of serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) and LOX-1 mRNA in peripheral mononuclear cells in early diagnosis of acute coronary syndrome].

OBJECTIVE: To assess the value of serum soluble lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) levels and LOX-1 mRNA expression in peripheral blood mononuclear cells in early diagnosis of acute coronary syndrome (ACS). METHODS: Enzyme-linked immunosorbent assay was used to detect the levels of plasma ox-LDL and LOX-1 in 95 patients with ACS, 60 with stable angina pectoris (SAP) and 40 normal control subjects. The expression of LOX-1 mRNA in peripheral blood mononuclear cells was detected by RT-PCR in the 3 groups. RESULTS: The levels of ox-LDL, LOX-1 and LOX-1 mRNA in the peripheral blood mononuclear cells were significantly higher in ACS patients than in SAP patients and normal control subjects (P<0.05). In ACS group, the level of plasma ox-LDL was significantly correlated to serum LOX-1 and LOX-1 mRNA expression in peripheral mononuclear cells. CONCLUSION: The level of plasma soluble LOX-1 and LOX-1 mRNA in peripheral mononuclear cells are significantly increased in ACS, and when combined, they provide a useful means for detecting ACS in the prophase.

[Clinical utilization of veiled incision and sternocleidomastoid flap in parotidectomy of parotid benign tumors].

PURPOSE: To describe a modified technique of parotidectomy using face-lift approach and sternocleidomastoid flap. METHODS: Forty-six patients were divided into two groups; group 1 (23 cases) using veiled incision and sternocleidomastoid flap, group 2 (23 cases) using traditional incision (Blair's approach) without sternocleidomastoid flap. Postoperative complications included temporary facial paralysis and salivary fistula. The follow-up period was 2 years, oncological recurrence was compared between the two groups. The incidence of Frey's syndrome and the feeling of the region around the auricular lobule were evaluated. The data was analyzed using SPSS10.0 software package with Student's t test and Chi-square test. RESULTS: During the follow up period, the patients in the group 1 showed better aesthetic results than those in the group 2 and without obvious scar and deformity. There was no significant difference between these two groups in temporary facial paralysis, salivary fistula, tumor recurrence, Frey's syndrome, the feeling of the region around the auricular lobule. CONCLUSION: The modified technique of parotidectomy using veiled incision and sternocleidomastoid flap greatly reduces the disadvantages of traditional parotidectomy and provides better aesthetic results.

[p38 MAPK mediates high glucose-induced renal tubular epithelial-mesenchymal transition.].

The aim of the present study was to investigate the role of p38 MAPK in the renal tubular epithelial-mesenchymal transition (TEMT) induced by high glucose. In in vivo study, the rats were randomly divided into control (C), diabetes mellitus (DM) and insulin-treated DM groups. Immunohistochemical staining and Western blot were employed to determine the expression of p38 MAPK and p-p38 MAPK protein in renal cortex of rats. In in vitro study, primary renal tubular epithelial cells (PTECs) were cultured with normal glucose (5.5 mmol/L), high glucose (20 mmol/L D-glucose), high osmolality (20 mmol/L D-mannitol) and SB202190 (a p38 MAPK inhibitor) plus high glucose respectively for 72 h. The expressions of p38 MAPK, p-p38 MAPK, Snail1, transforming growth factor-beta1 (TGF-beta1), alpha-smooth muscle actin (alpha-SMA) and E-cadherin protein and mRNA were detected by immunocytochemical staining, Western blot and RT-PCR. The p38 MAPK and p-p38 MAPK were specifically upregulated by high glucose in both in vivo and in vitro studies. The p38 MAPK activation was abolished by insulin controlling hyperglycemia to normal level in DM rats and inhibited dramatically by SB202190 in high glucose-cultured PTECs. The protein and mRNA of alpha-SMA were markedly increased in PTECs cultured with high glucose and were 12-fold and 8-fold respectively over that in the normal glucose, which were significantly suppressed by SB202190. SB202190 down-regulated the high glucose-induced Snail1 protein expression in PETCs, and restored partly the depression of E-cadherin protein and mRNA. These results suggest that p38 MAPK mediates high glucose-induced TEMT via transcription factor Snail1.

[Transforming growth factor-ß1 and Snail1 mediate tubular epithelial-mesenchymal transition in diabetic rats].

The present study was aimed to explore the expressions of transforming growth factor-ß1 (TGF-ß1) and Snail1 in renal tissues of diabetic rats, and their role in tubular epithelial-mesenchymal transition (TEMT). Induced diabetic rats were randomly divided into 2-, 4-, 8-, 12-, 16-, 20-, 24-week and 16wA, 20wA, 24wA groups. The rats in 16wA, 20wA and 24wA groups were treated with insulin to control blood glucose to the normal level from the 13th week. The age-matched rats were set as controls. Blood glucose, 24-hour urine protein, serum creatinine (Scr), kidney index of rats were measured. PAS staining was used to observe the renal pathological changes. Immunohistochemical staining and (or) Western blot were employed to determine the expressions of TGF-ß1, Snail1, E-cadherin, α-smooth muscle actin (α-SMA) and fibronectin (FN) proteins. The expressions of Snail1 and E-cadherin mRNAs in renal cortex were examined by RT-PCR. Blood glucose, 24-hour urine protein, Scr and kidney index increased remarkably in diabetic rats as compared with those in the control groups (P<0.05, P<0.01) and insulin-treated rats (P<0.01). TGF-ß1 and Snail1 protein expressions could not be detected by immunohistochemical staining in the normal renal tissues, however, the strongly positive staining was observed in diabetic rat renal tubules. A time-dependent loss of TGF-ß1 and Snail1 expressions was detected in the kidney of insulin-treated rats. In diabetic rats tubular α-SMA positive staining was seen at the 16th week. E-cadherin expression was lost in diabetic rats. The expressions of TGF-ß1, Snail1 proteins and Snail1 mRNA were significantly up-regulated in diabetic rats, while down-regulated in insulin-treated rats (P<0.01). The expressions of E-cadherin protein and mRNA in the cortex were contrary to the expressions of TGF-ß1 and Snail1. Therefore, TGF-ß1 and Snail1 are possibly involved in the pathogenesis of TEMT in diabetic nephropathy rats.

[The enhancement and inhibition of lucigenin chemiluminescence by phenol and aniline derivatives].

The effect of phenol and aniline derivatives on the lucigenin-H2O2-Co2+ chemiluminescence (CL) at different pH was studied. In NaHCO-Na2CO3 medium, some compounds enhanced the lucigenin CL while others inhibited the lucigenin CL. In NaOH medium, all tested compounds inhibited the lucigenin CL. It was found that the magnitude of enhancement and inhibition by tested compounds was related to their molecular structures, media, and pH. The fluorescence spectra of the system after the CL reaction and the CL spectra of the lucigenin system were studied. The possible mechanisms for CL enhancement and inhibition have been proposed. On the one hand, the competition of phenol and aniline derivatives with lucegenin for H2O2/HO2(-) led to the inhibition. On the other hand, the nucleophilic adducts of lucigenin formed by the reactions of some phenol and aniline derivatives with lucegin reacted with lucigenin to give rise to lucigenin radicals, followed by the reactions with the dissolved oxygen to give CL, resulting in the enhancement. The competition of these two routes led to the CL enhancement or inhibition under different conditions.

[Alprazolam use improves psychological status and reduces hospitalization costs in patients with paroxysmal supraventricular tachycardia underwent radiofrequency catheter ablation].

OBJECTIVE: To evaluate the effect of alprazolam use on psychological status and hospitalization cost in patient with paroxysmal supraventricular tachycardia underwent electrophysiology studies or radiofrequency catheter ablation. METHODS: In this prospective, randomized, double-blind, placebo-controlled study, 142 inpatients [77 males, mean age (43.1 +/- 14.5) years] were randomly assigned to receive alprazolam (0.4 mg qd at 10PM for 3 days, n = 72) or placebo (n = 70) 3 days before scheduled electrophysiology studies or radiofrequency catheter ablation. All patients were examined by the Chinese version of Symptom Checklist-90 (SCL-90) at 24 hours before the procedure. RESULTS: Compared with the placebo group, the scores of somatization (1.38 +/- 0.40 vs. 1.65 +/- 0.56, P < 0.01), anxiety (1.50 +/- 0.39 vs. 1.69 +/- 0.50, P < 0.05), phobic anxiety (1.24 +/- 0.36 vs. 1.47 +/- 0.57, P < 0.01), psychotism constructs (1.24 +/- 0.34 vs. 1.35 +/- 0.30, P < 0.05) and global severity index (1.36 +/- 0.35 vs. 1.49 +/- 0.37, P < 0.05) were significantly decreased in alprazolam group. The hospitalization costs were also significantly lower in alprazolam group (32 498 +/- 1170) yuan compared to placebo group (32 947 +/- 1096) yuan, P < 0.05. CONCLUSION: The alprazolam use before electrophysiology studies and radiofrequency catheter ablation can improve the patients' psychological status and reduce the hospitalization costs.

Chemiluminescence accompanied by the reaction of gold nanoparticles with potassium permanganate.

It was found that potassium permanganate (KMnO(4)) could react with gold nanoparticles in a strong acid medium to generate particle size-dependent chemiluminescence (CL). For gold nanoparticles with the size of 2.6 or 6.0 nm, the reaction was fast and could produce the excited state Mn(II) with light emission around 640 nm. For gold nanoparticles larger than 6.0 nm, no light emission was observed due to a much slower reaction rate. The CL intensity was found to increase linearly with the concentration of 2.6 nm gold nanoparticles. The effects of the acid medium, concentration of KMnO(4) and presence of N(2) and O(2) were investigated. UV-Vis absorption spectra and X-ray photoelectron spectra (XPS) measured before and after the CL reaction were analyzed. A CL mechanism has been proposed suggesting that the potassium permanganate was reduced by gold nanoparticles in the strong acid medium to the excited state Mn(II), yielding light emission. The results bestow new light on the size-dependent chemical reactivities of the gold nanoparticles and on nanoparticle-induced chemiluminescence. The CL reaction was considered to be of potential use for bioanalysis applications.

Light emission of gold nanoparticles induced by the reaction of bis(2,4,6-trichlorophenyl) oxalate and hydrogen peroxide.

Light emission at approximately 415 nm was observed for gold particles with diameters of 2.6-6.0 nm dispersed in a solution containing bis(2,4,6-trichlorophenyl) oxalate and hydrogen peroxide. It was found that the light intensity was independent of the protecting reagents of the gold nanoparticles with similar size, the light intensity with gold nanoparticles of 5.0 and 6.0 nm in diameter was stronger than that with gold nanoparticles of 2.6 and 2.8 nm in diameter, and the light intensity increased linearly with the concentration of the gold nanoparticles using 6.0-nm gold nanoparticles. The gold nanoparticles were identified as emitting species, and the quantum yield was determined to be (2.8 +/- 0.3) x 10(-5) using 6.0-nm gold nanoparticles. The light emission is suggested to involve a sequence of steps: the oxidation reaction of bis(2,4,6-trichlorophenyl) oxalate with hydrogen peroxide yielding an energy-rich intermediate 1,2-dioxetanedione, the energy transfer from this intermediate to gold nanoparticles, and the radiative relaxation of the as-formed exited-state gold nanoparticles. The observed luminescence is expected to find applications in the field of bioanalysis owing to the excellent biocompatibility and relatively high stability of gold nanoparticles.

Chemiluminescent reactions induced by gold nanoparticles.

The reaction of gold nanoparticles with a potassium periodate-sodium hydroxide-carbonate system undergoes chemiluminescence with three emission bands at 380-390, 430-450, and 490-500 nm, respectively. It was found that the light intensity increased linearly with the concentration of the gold nanoparticles, and the CL intensity increased dramatically when the citrate ions on the nanoparticle surface were replaced by SCN(-). The shape, size, and oxidation state of gold nanoparticles after the chemiluminescent reaction were characterized by UV-visible absorption spectrometry, transmission electron microscopy (TEM), and X-ray photoelectron spectrometry (XPS). Gold nanoparticles are supposed to function as a nanosized platform for the observed chemiluminescent reactions. A chemiluminescent mechanism has been proposed in which the interaction between free CO(3)(*-) and O(2)(*-) radicals generated by a KIO(4)-NaOH-Na(2)CO(3) system and gold nanoparticles results in the formation of emissive intermediate gold(I) complexes, carbon dioxide dimers, and singlet oxygen molecular pairs on the surface of the gold nanoparticles. This work is not only of great importance for gaining a better understanding of the unique optical and surface properties and chemical reactivity of nanoparticles but also of great potential for developing new biosensing and immunolabeling technologies.

Effect of pH on inhibition and enhancement of luminol-H2O2-Co2+ chemiluminescence by phenolic compounds and amino acids.

The effect of pH on inhibition and enhancement of luminol-H2O2-Co2+ chemiluminescence (CL) by 18 phenolic compounds and 20 amino acids was studied. It was found that most of the tested compounds showed an inhibiting effect at lower pH and an enhancing effect at higher pH. At a midrange pH, for some phenolic compounds with two ortho-position -OH, both an inhibiting and an enhancing peak were simultaneously observed. UV-visible spectra of the tested phenolic compounds at different pH values were studied. The mechanism for CL inhibition and enhancement was proposed. It is likely that the competition of the -OH or the -NH2 group and other reducing groups in the molecules with luminol for O2*- led to the CL inhibition. A reaction of -COO(-) and quinone or ketone formed by phenolic compounds at higher pH via deprotonation with O2*- also resulted in the CL enhancement.