异常黑胆质成熟剂黄酮类化合物诱导HepG2细胞凋亡机制的研究

目的：观察异常黑胆质成熟剂中黄酮类化合物对人肝癌细胞株(HepG2)体外生长、凋亡及相关基因表达的调控作用,探讨异常黑胆质成熟剂黄酮类化合物诱导癌细胞凋亡及抗癌活性的物质基础及其作用机制。方法：采用四氮甲基唑蓝法(MTT)、琼脂糖凝胶电泳技术、流式细胞术及逆转录-多聚酶链式反应技术(RT-PCR)等,观察异常黑胆质成熟剂黄酮类化合物对HepG2生长、凋亡及凋亡基因调控的影响。结果：异常黑胆质成熟剂黄酮类化合物明显抑制HepG2细胞体外生长,HepG2细胞在sub-G₁期受到阻滞,并能诱导细胞发生凋亡,明显下调Bcl-2 mRNA表达水平,同时可上调p53,p21,Bax基因mRNA表达水平。结论：异常黑胆质成熟剂黄酮类化合物对癌细胞体外生长、凋亡及凋亡基因表达具有明显的调控作用。黄酮类化合物可能是异常黑胆质成熟剂发挥抗癌作用的主要活性成分,而抑制细胞生长、诱导细胞凋亡及调控凋亡基因表达等可能是其发挥抗癌活性的重要途径。     

Pharmacokinetic and pharmacodynamic drug interactions between digoxin and macrogol 4000, a laxative polymer, in healthy volunteers

AIMS: The aim of this study was to examine the bioequivalence between a single oral dose of digoxin administered alone and with a coadministration of macrogol 4000 (a laxative polymer) in 18 healthy volunteers. METHODS: This was an open, randomised, two-way cross-over study, with a single dose oral administration of 0.5 mg digoxin administered alone or in combination with macrogol 4000, 20 g day-1 during 8 days. Pharmacokinetics of digoxin, heart rate and PR ECG interval at rest were assessed. RESULTS: Macrogol 4000 coadministration was associated with a 30% decrease of digoxin AUC and a 40% decrease in its Cmax (P<0.05). Digoxin tmax and t1/2,z were not significantly altered. Heart rate and PR interval did not differ during the two therapeutic sequences, digoxin alone and digoxin in combination. CONCLUSIONS: Macrogol 4000 coadministration interacts with single-dose digoxin pharmacokinetics. This is most likely due to a reduction of the intestinal absorption of digoxin. However, there was no consequence of this interaction on heart rate and AV conduction.     

A limited-sampling strategy for estimation of etoposide pharmacokinetics in cancer patients

Etoposide (VP16), a widely used anticancer drug, is a topoisomerase II inhibitor. A number of studies have highlighted a correlation between hematologic toxicity and pharmacokinetic or physiological parameters. Other studies have also suggested that the anti-tumor response could be related to the plasma etoposide concentration. Therefore, it would seem of interest to individualize VP16 dose regimens on the basis of pharmacokinetic parameters. The aim of this study was to develop and validate a limited-sampling strategy allowing VP16 pharmacokinetic evaluation with minimal disturbance to the patient. A total of 34 patients (54 kinetics) received VP16 at various dose regimens, with doses ranging between 30 and 200 mg and infusion times varying between 0.5 and 2 h. The statistical characteristics of the pharmacokinetic parameters were assessed from the first courses of treatment performed in 23/34 patients; then the following three-sample protocol was designed: the end of the infusion and 5 and 24 h after the start of the infusion. For validation of the model the main pharmacokinetic parameters (clearance, half-lives, volume of distribution) were estimated in the 11 remaining patients by maximum-likelihood estimation (ML) and by Bayesian estimation (BE) using the three sampling times designed. Statistical comparison showed a good concordance between ML and BE estimates (the bias for clearance was –1.72%). The limited-sampling strategy presented herein can thus be used for accurate estimation of VP16 pharmacokinetic parameters. Received: 17 November 1997 / Accepted: 25 August 1998     

LU135252, an endothelin(A) receptor antagonist did not prevent pulmonary vascular remodelling or lung fibrosis in a rat model of myocardial infarction

The early intervention with endothelin(A) (ET(A)) receptor antagonists following coronary artery ligation has been shown to reduce the development of pulmonary hypertension, despite a lack of improvement in left ventricular function. The present study examined the contribution of pulmonary vascular remodelling and the progression of lung fibrosis in the development of pulmonary hypertension and the subsequent role of endothelin-1 in these processes in a rat model of myocardial infarction (MI). The administration of 60 mg kg(-1) per day of the specific ET(A) receptor antagonist LU135253 ((+)-(S)-2-(4, 6-dimethoxy-pyrimidin-2-yloxy)-3-methoxy-3,3-diphenyl-propionic acid) 24 h following coronary artery ligation, failed to improve left ventricular contractile indices, but reduced the extent of pulmonary hypertension, as reflected by the significant decrease in right ventricular systolic pressure. The medial wall thickness of small pulmonary arteries (50 - 200 microm) was significantly increased 4 weeks following MI, albeit LU135253 treatment did not ameliorate this pattern of vascular remodelling. The steady-state mRNA levels of collagen, fibronectin, transforming growth factor-beta(1), and -beta(3) were significantly increased in the lungs of MI rats. The treatment with LU135252 did not alter this pattern of gene expression. Thus, these data demonstrate pulmonary vascular remodelling and the increased expression of extracellular matrix proteins represent underlying mechanisms implicated in the development of pulmonary hypertension in the MI rat. Despite the amelioration of the pulmonary hypertensive state, ET(A) receptor blockade was insufficient to reverse pulmonary vascular remodelling, or the development of lung fibrosis in the MI rat.     

Nutritional Strategy in the Management of Heart Failure in Adults

The incidence of congestive heart failure (CHF) is increasing in Westernized countries, and patients with CHF experience poor quality of life (functional impairment, high hospitalization rate and high mortality). Malnutrition occurring during the course of CHF is referred to as cardiac cachexia and is associated with higher mortality independent of the severity of CHF. Cardiac cachexia involving a loss of more than 10% of lean body mass can clinically be defined as a bodyweight loss of 7.5% of previous dry bodyweight in a period longer than 6 months. The energy requirements of patients with CHF, whether cachectic or not, are not noticeably modified since the increase in resting energy expenditure is compensated by a decrease in physical activity energy expenditure. Malnutrition in CHF has been ascribed to neurohormonal alterations, i. e. anabolic/catabolic imbalance and increased cytokine release. Anorexia may occur, particularly during acute decompensation of CHF. Function is impaired in CHF, because of exertional dyspnea and changes in skeletal muscle. Decreased exercise endurance seems to be related to decreased mitochondrial oxidative capacities and atrophy of type 1 fibers, which are attributed to alteration in muscle perfusion and are partially reversible by training. Malnutrition could also impair muscle function, because of decreased muscle mass and strength associated with decreased glycolytic capacities and atrophy of type 2a and 2b fibres. With respect to the putative mechanisms of cardiac cachexia, anabolic therapy (hormones or nutrients) and anticytokine therapy have been proposed, but trials are scarce and often inconclusive. In surgical patients with CHF, perioperative (pre- and postoperative) nutritional support has been shown to be effective in reducing the mortality rate. Long term nutritional supplementation trials in patients with CHF and cachexia are thus required to establish recommendations for the nutritional management of patients with CHF.     

Robotic versus laparoscopic distal pancreatectomy: a French prospective single-center experience and cost-effectiveness analysis

Surgical Endoscopy - Benefits and cost-effectiveness of robotic approach for distal pancreatectomy (DP) remain debated. In this prospective study, we aim to compare the short-term results and real...     

Proteomics as the Tool to Search for Lung Disease Markers in Bronchoalveolar Lavage

Most lung disorders are known to be associated to considerable modifications of surfactant composition. Numerous of these abnormalities have been exploited in the past to diagnose lung diseases, allowing proper treatment and follow-up. Diagnosis was then based on phospholipid content, surface tension and cytological features of the epithelial lining fluid (ELF), sampled by bronchoalveolar lavage (BAL) during fiberoscopic bronchoscopy. Today, it appears that the protein content of ELF displays a remarkably high complexity, not only due to the wide variety of the proteins it contains but also because of the great diversity of their cellular origins. The significance of the use of proteome analysis of BAL fluid for the search for new lung disease marker proteins and for their simultaneous display and analysis in patients suffering from lung disorders has been examined.