Protective effects of morphine preconditioning in delayed phase on myocardial ischemia-reperfusion injury in rabbits.

The aim of this study was to investigate the protective mechanisms of delayed-phase morphine preconditioning on myocardial ischemia-reperfusion injury. Thirty healthy male New Zealand white rabbits were randomly divided into three groups: a sham operation group (C), ischemia-reperfusion group (I/R), and delayed-phase morphine preconditioning group (M) (N = 10/group). Rabbits in the C group received thoracotomy for 160 min. Rabbits in the I/R group received left artery blockage for 40 min and reperfusion for 120 min. Rabbits in the M group received 1.0 mg/kg intravenous morphine 24 h prior to the identical treatment as the rabbits in the I/R group. In each group, the interleukin (IL)-10 and tumor necrosis factor (TNF)-α levels were detected at five time points: 20 min before the left coronary artery blockage (T1), 20 and 40 min after the left coronary artery blockage (T2 and T3, respectively), and 1 and 2 h after the myocardial reperfusion (T4 and T5, respectively). After reperfusion, the infarction size was measured with Evans blue and 2,3,5-triphenyltetrazolium chloride (TTC) staining. Compared with the C group, serum IL-10 and TNF-α concentrations increased in the I/R and M groups; the difference was significant (P < 0.05). When compared with the I/R group, the IL-10 concentrations in the M group were significantly increased (P < 0.05), but the infarction size and TNF-α concentrations were significantly decreased (P < 0.05). These results suggested that delayed-phase morphine preconditioning might achieve myocardial protection through the regulation and balance of inflammatory cytokines.

Effect of morphine preconditioning in the delayed phase on the expression of p38 mitogen-activated protein kinase in a rabbit model of myocardial ischemia-reperfusion injury.

This study aimed to investigate the protective effects of delayed morphine preconditioning on myocardial ischemia-reperfusion injury. We randomly divided 30 rabbits into three groups with 10 rab-bits in each group as follows: sham operation group (C group), isch-emia-reperfusion group (I/R group), and morphine pretreatment group (M group). Rabbits in C Group received left coronary without blocking for 160 min. The left descending artery of rabbits in the I/R group was blocked for 40 min and reperfused for 120 min. Rabbits in the M group received intravenous administration of 1.0 mg/kg morphine; after 24 h, rabbits in this group received the same treatment as that administered to the I/R group. We determined tumor necrosis factor alpha (TNF-α) levels in blood samples from the internal carotid artery of rabbits in each group 20 min before occlusion of the left descending coronary artery, 20 and 40 min after occlusion of the left descending coronary artery, and 1 and 2 h after myocardial reperfusion. After 120 min of reperfusion, immunoblotting was used to measure the activity levels of myocardial p38 mitogen-activated protein kinase (MAPK); in addition, the infarct size was measured. Compared to the I/R group, the M group showed a significant decrease in TNF-α levels, p38 MAPK activity, and the myocardial infarct size (I/R group 37.8% ± 1.7% vs 21.5% ± 2.4%; P < 0.05). Thus, morphine preconditioning in the delayed phase may exert protective effects on myocardial I/R injury by inhibiting myocar-dial p38 MAPK activity and decreasing TNF-α production.

Effects of isoflurane preconditioning in the delayed phase on myocardial tumor necrosis factor alpha levels and caspase-3 protein expression in a rabbit model of ischemia-reperfusion injury.

This study aimed to investigate the protective effects and the mechanisms underlying these effects of isoflurane preconditioning in the delayed phase of myocardial ischemia-reperfusion injury. We randomly divided 30 healthy male New Zealand white rabbits into three groups with 10 rabbits in each group as follows: sham operation group (C group), ischemia-reperfusion group (I/R group), and 2.0% isoflurane preconditioning group (S group). Rabbits in the C group received thoracotomy for 160 min. Rabbits in the I/R group underwent left coronary artery occlusion for 40 min and reperfusion for 120 min. Rabbits in the S group received inhalation of 2.0% isoflurane and 100% oxygen for 2 h; after 24 h, rabbits in this group received the same treatment as that administered to rabbits in the I/R group. We examined the tumor necrosis factor alpha (TNF-α) levels in each group 20 min before occlusion of the left coronary, 20 and 40 min after occlusion of the left coronary artery, and 1 and 2 h after myocardial reperfusion. After reperfusion, immunoblotting was used to measure the myocardial caspase-3 expression levels, and the infarct size was measured using Evans blue and tetrazolium chloride staining. The levels of TNF-α and caspase-3 were lower in the S group than in the I/R group, and the myocardial infarct size decreased in the S group. Thus, isoflurane preconditioning in the delayed phase exerted protective effects by decreasing the myocardial caspase-3 expression and TNF-α production in a rabbit model of ischemia-reperfusion injury.

Ginkgo biloba extract postconditioning reduces myocardial ischemia reperfusion injury.

We examined the protective effects of Ginkgo biloba extract (EGb761) postconditioning on myocardial ischemia reperfusion injury in rabbits. Four groups of 8 white rabbits were allocated to: pseudo surgery group: the left coronary was lined without blocking for 160 min after thoracotomy; ischemia and reperfusion group (IR): the left anterior descending coronary artery was blocked for 40 min and reperfused for 120 min; ischemic postconditioning group: the left anterior descending artery was ligated for 40 min, reopened for 30 s and ligated for 30 s, repeated three times, and then reperfused for 120 min; EGb761 postconditioning group (E): 100 mg/kg EGb761 was injected into a vein while the left coronary artery was opened for 1 min. The reperfusion took 120 min. Internal carotid arterial blood in each group was collected for cTnI measurement at five times: 20 min before occlusion of the left coronary artery, 20 min after left coronary artery occlusion, 40 min after left coronary artery occlusion, 1 h after myocardial reperfusion, and 2 h after myocardial reperfusion. Superoxide dismutase (SOD), malondialdehyde (MDA) in the centrifuged blood and myocardial infarction area were measured at the end of reperfusion. We found that the serum cTnI concentrations in the E group during reperfusion decreased significantly compared with those in the IR group. The infarction area was significantly lower in the E group than that in the IR group. The SOD activity in the E group was increased compared with that in the IR group; the MDA content decreased significantly in the E group compared with that in the IR group. We conclude that G. biloba extract postconditioning had myocardial protection effects by reducing the generation of oxygen-free radicals and increasing the antioxidant capacity of the myocardial cells.

Effect of quercetin on P-glycoprotein transport ability in Chinese healthy subjects.

OBJECTIVES: The aim of this study was to investigate the effect of quercetin on P-glycoprotein (P-gp) transport ability in vivo. SUBJECTS/METHODS: Genotype data were available from a total of 165 health volunteers. An open, randomized, two-period crossover clinical trial was performed in eighteen subjects with different MDR1 3435 C/T genotypes. All subjects took 500 mg quercetin or placebo daily from 1st to 13th day or from 43 st to 55th day, and 100 mg talinolol was given at the 14th or 56th day. The washout period is 28 days. RESULTS: In this study, we found the values of area under the curve (AUC)0-48 h, AUC0-∞ and Cmax of talinolol in all subjects significantly decreased (6496.6 ± 2389.9 vs 7809.5 ± 2386.8 ng.h/ml, P=0.04), (8414.7 ± 344.8 vs 10478.2 ± 4195.4 ng.h/ml, P=0.03), (412.9 ± 132.6 vs 543.3 ± 97.9 ng.h/ml, P=0.01) after administration of quercetin, respectively. There were no significant differences in tmax and t1/2 of talinolol. The results also showed AUC0-48 h (5598.6 ± 2202.1 vs 8229.4 ± 1491.7 ng.h/ml, P=0.02) and AUC0-∞ (7110.0 ± 3437.0 vs 12681.2 ± 4828.2 ng.h/ml, P=0.01) of talinolol to be significantly decreased in MDR1 3435 TT individuals administered of quercetin. The Cmax of talinolol in MDR1 3435 TT (382.4 ± 149.1 vs 584.9 ± 115.2 ng/ml, P=0.04) and MDR1 3435 CT (383.5 ± 104.9 vs 554.6 ± 80.6 ng/ml, P=0.01) individuals significantly decreased after the administration of quercetin. CONCLUSIONS: Quercetin significantly induced the activity of P-gp and this induced effect was more obvious in MDR1 3435 TT individuals.

The wavelet-based cluster analysis for temporal gene expression data.

A variety of high-throughput methods have made it possible to generate detailed temporal expression data for a single gene or large numbers of genes. Common methods for analysis of these large data sets can be problematic. One challenge is the comparison of temporal expression data obtained from different growth conditions where the patterns of expression may be shifted in time. We propose the use of wavelet analysis to transform the data obtained under different growth conditions to permit comparison of expression patterns from experiments that have time shifts or delays. We demonstrate this approach using detailed temporal data for a single bacterial gene obtained under 72 different growth conditions. This general strategy can be applied in the analysis of data sets of thousands of genes under different conditions.

[The effect of 3',5'-cyclic adenylic acid (cAMP) on the growth of bacteria].

The effect of intracellular cAMP level on the growth of bacteria was studied with E. coli AS 1.797, Corynebacterium pekinense AS 1.299 and Bacillus megaterium AS 1.217. The experimental results show that the growth of E. coli AS 1.797 was decreased with increasing cAMP level in cell. With glucose as the sole carbon source, intracellular cAMP is low, and growth of E. coli AS 1.797 was inhibited by exogenous cAMP, but the analog metabolite of cAMP-5'-AMP had no effect on growth. When E. coli AS 1.797 was grown in media containing lactose, maltose and glycerin respectively, intracellular cAMP level is high, and exogenous cAMP did not inhibited the cell growth. When Corynebacterium pekinense AS 1.299 took glucose as carbon source the growth of this bacterium was also inhibited by exogenous cAMP, but the inhibition of cAMP was not specific, its role can be exchanged by 5'-AMP. B. megaterium AS 1.217 cultivated in different carbon source (include glucose) do not contain cAMP in cell, and its growth was not inhibited by exogenous cAMP. 5'-AMP had also no effect on the growth of this bacterium. Thus, the conclusion seems that the cAMP is not essential for the growth of bacteria, and it is a regulator that act a negative regulation in cell growth, but this regulator is of no effect for the growth of B. megaterium AS 1.217.