Development and validation of a sensitive HPLC method for the determination of lisinopril in human plasma after derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole

In this study, we developed a simple and sensitive HPLC method for the determination of lisinopril in human plasma. The sample clean-up was carried out by solid-phase extraction (SPE) using a cation-exchange (Strata-SCX^®) extraction cartridge. After a pre-column derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole, the reaction mixture was analyzed on an Agilent Zorbax SB^®-C₁₈ (150 mm×4.6 mm, 5 μm). The flow rate was set at 1.0 mL/min. Fluorescence detection was performed at an excitation wavelength of 470 nm and an emission wavelength of 530 nm. The mobile phase consisted of a mixture of methanol and 0.02 M sodium dihydrogen phosphate (pH = 3.0, 60:40, v/v). The average extraction recovery of lisinopril and fluvoxamine (internal standard) was >85%. The method exhibited a linear calibration curve over the concentration range of 1–1000 ng/mL with a correlation coefficient (r²) of ≥0.98 and a limit of quantification (LOQ) equal to 2 ng/mL. The within-run and between-run precisions were satisfactory with an RSD of 3.8%–13.7% (accuracy: from 95.0% to 96.4%) and 4.273%–14.3% (accuracy: from 94.4% to 98.5%), respectively.     

Effects of hemodynamic instability on brain death-induced prepreservation liver damage

BACKGROUND: Brain death (BD) is an important multifactorial variable contributing to donor-specific liver damage. Our study aimed at assessing the specific effects of hemodynamic instability on systemic and hepatic parameters of perfusion, bowel ischemia, and oxidative stress in a porcine model of BD. METHODS: BD was induced in 16 pigs (German Landrace, 18-28 kg) in two groups (hypotension-BD [HYPO-BD], n=8; normotension-BD [NORM-BD], n=8), which were compared with control animals/living donors (n=6) for a period of 2 hr. We analyzed systemic hemodynamic parameters, bowel ischemia (intramucosal pH in the stomach and colon, plasma endotoxin levels, and endotoxin-neutralizing capacity [ENC]), and oxidative stress (total glutathione levels in erythrocytes) and compared the findings with hepatic parameters of perfusion (hepatic arterial flow, portal venous flow, and microperfusion) and liver oxidative stress (reduced glutathione and oxidized glutathione levels in the liver). RESULTS: Independent of the hemodynamic stability, liver macrocirculation and microcirculation decreased (HYPO-BD, 79+/-6 to 69+/-10 mL/100 g/min; NORM-BD, 81+/-10 to 73+/-7 mL/100 g/min; P<0.05). Hepatocellular damage (aspartate aminotransferase: NORM-BD, 49+/-20 units/L; HYPO-BD, 170+/-140 units/L; P<0.01) and hepatic oxidative stress (reduced glutathione in the liver/oxidized glutathione in the liver: NORM-BD, 29.4+/-2.3 to 13.0+/-1.3; HYPO-BD, 29.4+/-2.3 to 9.05+/-0.81; P<0.001) increased in both BD groups. With dependence on systemic hemodynamic parameters, bowel ischemia increased (intramucosal pH in the colon, 7.22+/-0.01, P<0.01; ENC, 75+/-14 endotoxin-neutralizing units/mL, P<0.01; endotoxin levels, 7+/-2 to 43+/-10 pg/mL, P<0.01) in the HYPO-BD group but not in the NORM-BD group or the living donor group. Furthermore, systemic oxidative stress was increased in the HYPO-BD group only (total glutathione levels in erythrocytes, 2.65+/-0.25 to 0.15+/-0.25 mM; P<0.01). CONCLUSIONS: During BD, liver-specific parameters (portal venous flow, microperfusion, aspartate aminotransferase activity, ENC, and hepatic oxidative stress) were compromised, independent of the hemodynamic status. Therefore, the systemic hemodynamic status does not reflect the functional status of the liver during BD.     

CD4⁺Foxp3⁺ Treg and its ICOS⁺ Subsets in Patients with Myocardial Infarction

Background: Atherosclerosis is a multifactorial disorder with chronic inflammatory conditions in which immune cells play a significant role in its pathogenic process. Regulatory T cells (Treg), as a part of immune system, are involved in controlling auto-immune and inflammatory diseases. Tregs have been shown to play an atheroprotective role and may also promote plaque stabilization. Objective: To assess if inducible costimulatory molecule (ICOS) expression on one subtype of Treg cells with high suppressive potential correlates with the pathogenesis of atherosclerosis. Methods: Patients with myocardial infarction (MI) and/or stable angina (SA), diagnosed as atherosclerosis by angiography, and a group of individuals with normal coronary angiography (NCA) were recruited for the present study. Peripheral blood mononuclear cells (PBMCs) were prepared and the expression of ICOS, Foxp3 and CD4 molecules was tested by flowcytometry. Results: The percentage of CD4+Foxp3+ Treg cells was reduced in MI group compared to NCA and SA groups (p<0.005). Evaluation of the two Treg subsets according to ICOS expression showed a decreased ICOS+/ICOS- Treg ratio in MI and SA groups compared to NCA individuals (p=0.002 and p=0.048, respectively). Conclusion: The present data indicate that Tregs and its ICOS+ subsets are decreased in patients with MI or SA, suggesting a potential role for Treg in atherosclerosis progression or onset of acute coronary syndrome.     

Serum Interleukine-6 Concentration,But Not Interleukine-18, is Associated with Head and Neck Squamous Cell Carcinoma Progression

Inflammation has been linked to various steps in tumorigenesis. Interleukin (IL)-6 and IL-18 are two inflammatory cytokines whose serum concentrations are elevated in several types of cancer, including head and neck squamous cell carcinoma (HNSCC) in some studies. This study was designed to analyze the serum concentrations of these cytokines in Iranian HNSCC patients. Serum IL-6 and IL-18 concentrations were assayed by ELISA commercial kits in 65 untreated patients and 20 healthy volunteers. Serum IL-6 concentration was significantly increased in patients compared to healthy individuals (p < 0.000). IL-6 concentration increased as the tumor stage progressed, and a significant difference appeared between stage IV vs. stage I/II/III (p = 0.03) disease. Although serum IL-18 concentration was higher in patients than in healthy individuals, the difference was not statistically significant (p = 0.06). Moreover, there was no association between serum IL-18 concentration and tumor stage (p = 0.47). A significant difference was observed in serum IL-18 concentration according to the gender with higher IL-18 concentration in male patients (p = 0.01). In conclusion, serum concentration of IL-6 might correlate with the stage of tumor progression in Iranian HNSCC patients. Further studies with larger numbers of patients are required to exclude the possible minor correlation of serum IL-18 concentration with tumor stage.     

活体异体结膜缘和羊膜移植治疗化学性眼外伤造成的角膜缘干细胞缺失(英文)

目的:评价利用活体异体结膜缘和羊膜移植治疗化学性眼外伤造成的角膜缘干细胞缺失的临床效果。方法:从2005-07/2007-12,本研究包括了9名男性化学性眼外伤患者(10眼)。所有患者接受了亲属活体异体结膜缘和羊膜移植,2例眼接受了睑缝术。用环孢菌素和泼尼松龙进行全身性免疫抑制。结果:在3例眼中观察到完全角膜上皮化(30%),其中1例在术后1.5mo出现免疫排斥,角膜溶解引起穿孔,加大全身性免疫抑制剂量来控制病情。3例眼中植片无法在角膜表面重新形成上皮,被定为原发性失败。其余4眼有部分上皮形成,但上皮细胞无法完全覆盖角膜表面。术前最佳矫正视力从手动到1m处数指,术后最佳矫正视力从光感到20/80。有5眼视力得到改进,不需其他治疗。手术失败的主要原因为干眼症和持续性炎症。结论:对于能控制泪量和眼部炎症的病例,亲属活体异体角膜缘和羊膜移植是治疗化学性眼外伤造成的角膜缘干细胞缺失最佳方法之一。     

Experimental monitoring of hepatic glucose,lactate, and glutamate metabolism by microdialysis during surgical preparation of the liver hilus

Mechanical liver manipulation can lead to hepatic microcirculation (MC) impairment. The pathobiochemical relevance of this phenomenon is not fully understood. Microdialysis (MD) allows a quantification of metabolic products in interstitial fluid, thus enabling analysis of the hepatic metabolic state during changes of liver perfusion. The aim of the study was to quantify the functional effects of standardized surgical liver preparation both on liver metabolism and microperfusion. Two groups of animals (pigs, n = 25) were formed: In the trial group (TG; n = 13) the liver was mobilized, followed by hilar preparation. In the control group (CG; n = 12) mobilization of the liver without hilar dissection was performed. Surgical manipulation was followed by an observation in both groups. Hepatic interstitial glucose, lactate, and glutamate concentrations were detected by MD and liver MC by thermodiffusion. During liver mobilization MC decreased significantly in both groups (TG; 86.7 +/- 2.0 to 73.4 +/- 2.3 ml/100 g min; and CG; 88.3 +/- 3.1 to 71.9 +/- 2.2 ml/100 g/min). In the trial group levels decreased further during hilar preparation reaching minimal values of 65.6 +/- 2.8. After preparation MC recovered to baseline. Glucose, lactate, and glutamate concentrations increased significantly during liver mobilization in the trial (glucose; 0.52 +/- 0.13 to 0.88 +/- 0.19 mmol/L; lactate; 0.34 +/- 0.07 to 0.54 +/- 0.07 mmol/L; glutamate; 34.5 +/- 3.6 to 52.6 +/- 8.0 micromol/L) and control group (glucose; 0.58 +/- 0.06 to 0.95 +/- 0.13 mmol/L; lactate; 0.30 +/- 0.06 to 0.49 +/- 0.07 mmol/L; glutamate; 32.9 +/- 2.36 to 56.1 +/- 5.12 micromol/L). Throughout hilus preparation maximum values could be measured in TG (glucose; 1.69 +/- 0.34; lactate; 0.90 +/- 0.18; glutamate; 63.5 +/- 7.2). After termination of mobilization or preparation baseline concentrations were reached again. MD allows monitoring of metabolic changes in hepatic parenchyma. Surgical liver preparation leads to changes of intrahepatic glucose, lactate, and glutamate levels (without alterations of parameters in systemic plasma) along with hepatic MC impairment. Reconstitution of hepatic MC was accompanied by rapid normalization of metabolic parameters. By measuring specific parameters, MD could prove to be of use for functional assessment of metabolic effects due to MC disturbances.     

Analysis of Fgf15 expression pattern in the mouse neural tube

The dynamic process of neural tube regionalization in vertebrates is regulated by the expression of developmental genes which appear in characteristic patterns at neuroepithelial transversal domains, which are called secondary organizers. The molecular code present in these neuroepithelial organizers controls the generation of morphogenetic signals that induce and maintain regional characteristics in the surrounding neuroepithelium. The product of the Fgf8 gene is a secreted protein that has been demonstrated to be the key molecule for the isthmic organizer and is also expressed in two other organizer regions: the zona limitans and the anterior neural ridge. Here we analyze the expression of Fgf15 at different stages of mouse development in relation to Fgf8 and Otx2 expression patterns.     

Outcome of major cardiac injuries at a Canadian trauma center

Background  

Canadian trauma units have relatively little experience with major cardiac trauma (disruption of a cardiac chamber) so injury outcome may not be comparable to that reported from other countries. We compared our outcomes to those of other centers.     

Zinc and ascorbic acid coordinately promote lipid peroxidation in brain membranes

Zn2+ is present at high concentrations in mammalian brain, and is released in chelatable form after excitation of certain glutamatergic neurons. Recent observations suggest that it may play an important role in excitotoxic-induced neural injury. Ascorbic acid has been widely studied as a stimulator or an inhibitor of lipid-peroxide formation, depending on concentration, and lipid peroxidation has been postulated to be involved in both acute and chronic neurogenerative diseases. We find that ascorbic acid and Zn2+, at concentrations that are achieved in the brain after prolonged synaptic depolarization, coordinately promote lipid-peroxide formation and cause dysfunction of membrane-bound proteins. This effect is unique to Zn2+, and other divalent cations do not share a similar synergism with ascorbate. We propose that the Zn2+-ascorbate interaction may be an overlooked mechanism of lipid-peroxide formation in brain injury.