A Pharmacokinetic and Pharmacodynamic Study of Intravenous Levosimendan in Healthy Chinese Volunteers and Ethnic Comparisons.

BACKGROUND: The objective of this study was to assess the pharmacokinetics and pharmacodynamics of intravenous levosimendan and the metabolites (OR1855 and OR1896) in healthy Chinese male subjects and to post hoc compare with Caucasian subjects. METHODS: One single 2 mg dose of levosimendan was infused intravenously over 10 minutes to each of 14 healthy male subjects. Plasma levosimendan was analyzed by high performance liquid chromatography. Pharmacodynamics was evaluated using echocardiography. RESULTS: The Cmax (peak concentration) and AUC∞ (area under the curve from time 0 to infinity) of levosimendan of Chinese subjects were significantly higher than for Caucasian subjects as 256.1 ± 37.8 (mean ± SD) vs. 142.1 ± 17.5 ng/mL and 207.5 ± 35.2 vs. 117.0 ± 17.0 hr·ng/mL, respectively. The clearance of Chinese subjects was significantly lower than Caucasian subjects at 9.9 ± 1.8 vs. 17.4 ± 2.7 L/hr, respectively. The elimination half-life of Chinese subjects was significantly longer than for Caucasian subjects (1.18 ± 0.18 vs. 0.76 ± 0.10 hr, respectively). Chinese subjects eliminated levosimendan significantly slower than Caucasian subjects, leading to a higher exposure of levosimendan in Chinese subjects. However, this higher exposure did not significantly change the most pharmacodynamic properties of levosimendan except for ejection fraction (EF). The EF increased 12.2 ± 11.4% in Chinese subjects 20 min after the end of intravenous infusion, which was significantly lower than Caucasian subjects with EF increased by 22.7 ± 7.0%. CONCLUSIONS: The intravenous levosimendan in healthy Chinese volunteers was safe, and well-tolerated with significant inotropic effect. The clearance of levosimendan of Chinese subjects was significantly lower and elimination half-life longer than Caucasian subjects. KEY WORDS: Chinese; Ethnic comparison; Levosimendan; Pharmacodynamics; Pharmacokinetics; Volunteer.

Activation of Krüppel-Like Factor 2 with Ginkgo Biloba Extract Induces eNOS Expression and Increases NO Production in Cultured Human Umbilical Endothelial Cells.

BACKGROUND: The mechanisms responsible for the effects of Ginkgo biloba extract (GbE) are not fully understood. Krüppel-like factor 2 (KLF2), a zinc transcription factor, has vasculoprotective effects if activated. The present study attempted to explore whether GbE may activate KLF2 and its consequences. METHODS: To determine the effects of GbE on endothelial cells, human umbilical vein endothelial cells (HUVECs) were incubated with various concentrations of GbE. KLF2 expression levels were determined by quantitative reverse transcription polymerase chain reaction. Cytoskeleton staining and cell migration assays were performed to determine the effects of KLF2 activation. Moreover, endothelial NO synthase (eNOS) expression levels were detected by PCR and Western blot testing. Nitric oxide (NO) production was also measured with 4,5-diaminofluorescein. A knockdown of KLF2 was performed to identify the role of KLF2 in GbE-induced eNOS expression and NO production. RESULTS: HUVECs that were incubated with GbE increased KLF2 expression. These cells demonstrated an altered cell morphology, cytoskeleton rearrangement, and inhibited migration activity. Moreover, eNOS expression and NO production increased in a dose-dependent manner when cells were treated with GbE. Correspondingly, silencing of KLF2 in HUVECs decreased eNOS expression and NO production in GbE-treated cells. CONCLUSIONS: GbE significantly activated KLF2 expression and KLF2-related endothelial function, including cytoskeleton rearrangement, inhibition of migration, eNOS activation, and NO production. These findings suggest that GbE may induce a vasculoprotective effect in endothelial cells. KEY WORDS: Endothelial cells; eNOS; Ginkgo biloba extract; KLF2; NO.

Pharmacokinetics of oral rosiglitazone in Taiwanese and post hoc comparisons with Caucasian, Japanese, Korean, and mainland Chinese subjects.

PURPOSE: Rosiglitazone, an insulin-sensitizing thiazolidinedione, acts as a ligand for the y-subtype of the peroxisome proliferator-activated receptor in the regulation of glucose homeostasis and lipid metabolism. The aims of this study were to determine the pharmacokinetics of oral rosiglitazone in Taiwanese and to post hoc compare the ethnic differences among Caucasian, Japanese, Korean, and Mainland Chinese. METHODS: Twelve Taiwanese healthy male subjects received 4 and 8 mg of rosiglitazone. Similar protocols were used in the previously unpublished studies conducted in 25 Caucasian, 32 Japanese, 8 Korean, and 12 Mainland Chinese healthy male subjects. The 4 mg dose data were used for ethnicity comparisons. RESULTS: The respective pharmacokinetic properties of Taiwanese, Caucasian, Japanese, Korean and Mainland Chinese are: terminal half-life (hr): 4.18 +/- 0.43, 3.96 +/- 1.31, 3.83 +/- 0.78, 4.70 +/- 1.19 and 4.37 +/- 0.63; Cmax (ng/ml): 384.1 +/- 59.3, 260.2 +/- 75.7, 401.9 +/- 102.3, 345.3 +/- 60.6, and 406.2 +/- 52.0; AUC0-inf (h*ng/ml): 2078 +/- 433, 1249 +/- 566, 1901 +/- 397, 1938 +/- 534, and 2158 +/- 498. The Cmax and AUC0-inf of Caucasian were significantly (p = 0.002, 0.008) lower and CL/F and V/F were significantly (p = 0.000, 0.003) higher than those of other races. These differences of Cmax, AUC0-inf, CL/F and V/F between Caucasian and other races became insignificant after normalized by dose and weight. CONCLUSIONS: In a given dose by body weight, ethnicity had no significant impact on the pharmacokinetics of rosiglitazone in normal healthy volunteers.

Cerebral hemorrhage in infective endocarditis caused by Actinobacillus actinomycetemcomitans.

Cerebral hemorrhage occurs rarely in endocarditis caused by Actinobacillus actinomycetemcomitans. A 51-year-old man with a prosthetic mitral valve, who had been prophylactically treated (7 years) with warfarin, presented with intermittent fever. On admission, a Levine grade II/VI systolic cardiac murmur was detected. A transthoracic echocardiogram was negative for valve vegetation. Cefepime (1 g every 8 hours) was administered intravenously. On day 4, culturing of Gram-negative bacilli from blood and a transesophageal echocardiogram revealed a small oscillating filament attached to lateral mitral prosthetic ring on the atrial side. Ceftriaxone (2 g once daily) was started. Gait instability and left-side weakness developed abruptly 2 weeks later; brain magnetic resonance imaging revealed a hematoma over the right parietal-occipital lobe. Ceftriaxone was adjusted to 2 g every 12 hours. Actinobacillus actinomycetemcomitans was identified 3 weeks later. Recovery was achieved, with significant interval improvement and resolution of the cerebral lesions evident on CT.

Effect of rosuvastatin on plasma levels of asymmetric dimethylarginine in patients with hypercholesterolemia.

Elevated plasma levels of asymmetric dimethylarginine (ADMA) have been associated with attenuated endothelium-dependent vasodilation in hypercholesterolemic patients. However, whether lowering of plasma cholesterol concentration by hydroxymethylglutaryl coenzyme A reductase inhibitors (statins) can reduce plasma ADMA levels is still not clear. This study was a multicenter, randomized, double-blind, placebo-controlled design including 46 patients with elevated low-density lipoprotein cholesterol levels. Patients were randomized into 2 groups: rosuvastatin 10 mg/day and placebo for 6 weeks. Plasma levels of ADMA, 8-isoprostane (as a marker of oxidative stress), homocysteine, and high-sensitivity C-reactive protein were measured at baseline and 6 weeks later. Endothelial function assessed by flow-mediated vasodilation of the brachial artery was performed in 11 patients in the rosuvastatin group and in 12 in the placebo group. Baseline characteristics of both groups were similar, and the plasma ADMA levels were significantly correlated with 8-isoprostane (r = 0.388, p = 0.008). After 6 weeks of treatment, plasma ADMA levels were significantly reduced in the rosuvastatin group (from 0.60 +/- 0.19 to 0.49 +/- 0.10 micromol/L, p <0.001). Increases in flow-mediated vasodilation were positively correlated with reductions in plasma levels of ADMA (p = 0.017) and low-density lipoprotein cholesterol (p <0.001). Thus, our findings suggest that treatment with rosuvastatin in patients with hypercholesterolemia may lead to a significant reduction in plasma ADMA levels, which appear to be related to the improvement in endothelial function by rosuvastatin.

The modulatory mechanisms of fenofibrate on human primary T cells.

Fenofibrate is a lipid-lowering agent and supposed to have anti-inflammatory properties. But it was rarely evaluated for the signal transduction on human primary T cells. Therefore, the methods including enzyme-linked immunosorbent assay (ELISA), electrophoretic mobility shift assay, luciferase assay and Western blotting were used to investigate the mechanisms of fenofibrate on human primary T cells, isolated from normal human beings. We found that fenofibrate could dose-dependently inhibit cytokine production such as interleukin-2, interleukin-4, tumor necrosis factor-alpha and interferon-gamma from activated T cells. Also, it could down-regulate activator protein-1 (AP-1) DNA-binding activities in T cells. As performing in vivo study, fenofibrate reduced the AP-1 transcriptional activity in Jurkat cells. Finally, fenofibrate inhibited the activation of c-Jun NH2-terminal protein kinase and P38 mitogen-activated protein kinase. These results may extend potential therapeutic mechanisms of fenofibrate on cardiovascular disease with inflammatory processes.

Flailed tricuspid valve as a complication of retrieving fractured catheter.

The implantable venous port system has gained popularity as venous access when prolonged chemotherapy is needed in cancer patients. Intravascular fracture and embolization of catheter fragments from port-catheter systems is rare. Here we report a 49-year-old lady who was found having a fractured port-catheter located over the right ventricular outflow tract (RVOT). Percutaneous transfemoral transcatheter retrieval of the fractured catheter was performed but complicated with flailed tricuspid valve.