组蛋白去乙酰化酶抑制剂与5-FU合用对肝癌细胞HepG2的影响

目的：探讨MS-275和5-Fu联用对HepG2细胞周期和凋亡的影响，并对其机制进行初步探讨。方法：将细胞分成对照组、MS-275组、5-FU组和联合用药组。流式细胞仪检测各组细胞凋亡和周期变化；Westernblot分析各组Bcl-2、Bax、CyclinD1、P21蛋白表达。结果：MS-275和5-Fu联用能抑制肝癌细胞生长，诱导G0—G1期阻滞，促进细胞凋亡。上述效应具有时间和剂量依赖性。二者联用可以使P21蛋白上调，Bcl-2、CyclinD1蛋白下调，Bax蛋白无明显变化。结论：5-Fu和MS-275联用能提高HepG2细胞凋亡率和周期阻滞，其机制与下调CyclinD1、Bcl-2蛋白的表达、上调P21蛋白表达有关。     

Interaction of class III antiarrhythmic drugs with muscarinic M2 and M3 receptors: radioligand binding and functional studies

We have recently reported that class III antiarrhythmic drugs inhibit the muscarinic acetylcholine (ACh) receptor-operated K⁺ current (I _K, ACh) in guinea-pig atrial cells by different molecular mechanisms. The data obtained from the patch-clamp study suggest that d,l-sotalol inhibits I _{K, ACh} by blocking the muscarinic receptors, whereas MS-551 inhibits the K⁺ current by blocking the muscarinic receptors and depressing the function of the K⁺ channel itself and/or the guanine nucleotide-binding protein (G protein). This study was undertaken to determine whether the class III antiarrhythmic drugs d,l-sotalol and MS-551 interact with the muscarinic receptors of cardiac and peripheral tissues. Both drugs inhibited concentration dependently the specific [³H]N-methylscopolamine ([³H]-NMS) binding to membrane preparations obtained from guinea-pig atria and submandibular glands. The competition curves of these drugs for [³H]-NMS binding to glandular membranes were monophasic, suggesting competition with [³H]-NMS at a single site. Although the competition curve of d,l-sotalol for [³H]-NMS binding to atrial membranes was monophasic, that of MS-551 was biphasic and showed high- and low-affinity states of binding. d,l-Sotalol showed slightly, but significantly, higher affinity for cardiac-type muscarinic receptors (M₂) than for glandular-type muscarinic receptors (M₃). The inhibition constant (K _i) for MS-551 in glandular membranes was also slightly greater than the high-affinity K _i value for the drug in atrial membranes. In guinea-pig left atria and ilea, d,l-sotalol shifted the concentration-response curves for the negative inotropic effect and the contracting effect of carbachol in a parallel manner. The slopes of Schild plot were not significantly different from unity, suggesting competitive antagonism, and the pA₂ for d,l-sotalol in left atria was slightly greater than that in ilea. MS-551 also shifted the concentration response curve for the negative inotropic effect of carbachol in atrial preparations to a greater extent than that for the contracting effect in ileal preparations, although MS-551 failed to show a pure competitive antagonism. These results suggest that both d,l-sotalol and MS-551 interact with cardiac M₂ and peripheral M₃ receptors, and that at high concentrations they exert anticholinergic activity in cardiac and peripheral tissues.     

Brief overview of selected approaches in targeting pancreatic adenocarcinoma

Introduction: Pancreatic adenocarcinoma (PDAC) has the worst prognosis of any major malignancy, with 5-year survival painfully inadequate at under 5%. Investigators have struggled to target and exploit PDAC unique biology, failing to bring meaningful results from bench to bedside. Nonetheless, in recent years, several promising targets have emerged.

Areas covered: This review will discuss novel drug approaches in development for use in PDAC. The authors examine the continued efforts to target Kirsten rat sarcoma viral oncogene homolog (KRas), which have recently been successfully abated using novel small interfering RNA (siRNA) eluting devices. The authors also discuss other targets relevant to PDAC including those downstream of mutated KRas, such as MAPK kinase and phosphatidylinositol 3-kinase.

Expert opinion: Although studies into novel biomarkers and advanced imaging have highlighted the potential new avenues toward discovering localized tumors earlier, the current therapeutic options highlight the fact that PDAC is a highly metastatic and chemoresistant cancer that often must be fought with virulent, systemic therapies. Several newer approaches, including siRNA targeting of mutated KRas and enzymatic depletion of hyaluronan with PEGylated hyaluronidase are particularly exciting given their early stage results. Further research should help in elucidating their potential impact as therapeutic options.     

In vivo imaging of retinoic acid receptor beta2 transcriptional activation by the histone deacetylase inhibitor MS-275 in retinoid-resistant prostate cancer cells

BACKGROUND: In retinoid resistant epithelial tumors, the lack of retinoic acid receptor beta2 (RARbeta2) expression due to epigenetic silencing impairs the activation of retinoid target genes including RARbeta2, and has been associated with the development of cancer. In this study we developed a strategy to monitor the re-activation of RARbeta2 by chromatin remodeling agents combined with retinoids in real time, and to correlate the RARbeta2 re-activation with anti-tumor activity. METHODS: We selected the RARbeta2-negative retinoid resistant human prostate carcinoma cell line PC3 and stably transfected it with a luciferase expression vector under the control of a functional segment of RARbeta2 promoter (pGL2-RARbeta2-PC3). Then, we used the bioluminescence technology to monitor the reporter gene expression in real time both in vitro and in vivo following combination treatment with the histone deacetylase inhibitor MS-275 and 13-cis retinoic acid (CRA). Based on the effective dose for the RARbeta2 re-activation, we tested the anti-tumor activity of this drug combination. RESULTS: Following combination treatment with MS-275 and CRA, we observed endogenous RARbeta2 re-expression, acetylation at the RARbeta2 promoter level, and synergistic activation of the luciferase reporter gene by real time imaging both in vitro and in vivo. Combination treatment with MS-275 and CRA restored retinoid sensitivity in human prostate carcinoma cell lines, and had a greater inhibitory effect on tumor cell growth than single agents in vitro and in vivo. CONCLUSIONS: This study provides evidence that HDAC inhibitors restore retinoid sensitivity in prostate cancer cells, and in vivo real time imaging of RARbeta2 activation may represent a useful tool to study the pharmacodynamics of combination therapy with HDAC inhibitors and retinoids.     

Vaginal morphology following hysterectomy

This study was designed to gain more information about morphology of the vagina after hysterectomy. The prospective clinical observations of patients subjected to abdominal or vaginal extrafascial or intrafascial hysterectomy with or without correction of anatomical urinary stress incontinence were included. The length, configuration and axis of the vagina were determined using a vaginal cast technic. Vaginal casts were prepared prior to and 6 months to 4 years after surgery. The gross appearance of the vagina after hysterectomy is affected by understanding normal pelvic anatomy an physiology, careful preoperative evaluation of pelvic defects, proper planning and competent performance of surgery. Proper handling of the endopelvic fascia and its condensations, the cardinal and sacrouterine ligaments, corrects preexisting weakness, provides vaginal suspension and prevents future vaginal disfigurement. Inadequate surgical technics result in magnifying preexisting weakness of pelvic supports. Successful surgery involves correcting the levator complex by reducing and shifting the levator hiatus ventrally. Reconstruction of the perineal body is essential. This study suggests a relationship between successful surgical treatment of urinary stress incontinence and reconstruction of pelvic supportive structures, with restoration of the physiological vaginal axis.     

Cellular electrophysiological effects of MS-551, a new class III antiarrhythmic agent

The cellular electrophysiological effects of MS-551, a pure class III antiarrhythmic agent lacking beta-blocking activity, were compared with those of d-sotalol and dofetilide in canine Purkinje fibers and ventricular muscles and in guinea pig atrial muscles using the standard microelectrode technique. MS-551 prolonged the action potential duration (APD) of these cardiac tissues to the same extent in a concentration-dependent manner (10^?6?10^?4 M). MS-551 did not affect other action potential parameters of these tissues except for the V_max, which was depressed approximately 10% at 10^?4 M MS-551. The extents of prolongation after 10^?5 M of MS-551 were 36, 27, and 35% for canine Purkinje and ventricular muscle and guinea pig atrial muscle, respectively. d-Stalol at a concentration 10 times higher than MS-551 produced a similar prolongation of the APD of canine cardiac tissues but only a slight prolongation of the APD of guinea pig atrial muscles. Dofetilide at a concentration 30 times lower than MS-551 produced a prolongation of the APD of canine Purkinje fibers but a relatively slight prolongation of the APD of both canine ventricular muscles and guinea pig atrial muscles. In canine Purkinje fibers, MS-551 did not prevent the APD shortening induced by high extracellular potassium (8 and 12 mM), but the APD under these conditions was lengthened compared with controls. Under simulated ischemic conditions (pO₂ 25–30 mmHg, pH 6.5, extracellular K 8 mM and no glucose) for 30 min, the APD was abruptly shortened during the first 5 min, then gradually shortened further up until 30 min. MS-551 did not prevent the abrupt APD shortening, but slowed the later gradual shortening. The APD prolonging action of MS-551 was enhanced at low frequency. These data indicate that (1) MS-551 is a pure class III antiarrhythmic agent with electrophysiological characteristics basically similar to d-sotalol and dofetilide; (2) MS-551 has a relatively greater potency in guinea pig atrial muscle than d-sotalol and dofetilide; (3) the APD prolonging action of MS-551 is preserved under high K⁺ or simulated ischemic conditions; and (4) MS-551 exhibits a reverse use-dependence in prolonging APD. © 1995 Wiley-Liss, Inc.     

New immunomodulatory role of neuropeptide Y (NPY) in Salmo salar leucocytes

Neuropeptide Y (NPY) plays different roles in mammals such as: regulate food intake, memory retention, cardiovascular functions, and anxiety. It has also been shown in the modulation of chemotaxis, T lymphocyte differentiation, and leukocyte migration. In fish, NPY expression and functions have been studied but its immunomodulatory role remains undescribed. This study confirmed the expression and synthesis of NPY in S. salar under inflammation, and validated a commercial antibody for NPY detection in teleost. Additionally, immunomodulatory effects of NPY were assayed in vitro and in vivo. Phagocytosis and superoxide anion production in leukocytes and SHK cells were induced under stimulation with a synthetic peptide. IL-8 mRNA was selectively and strongly induced in the spleen, head kidney, and isolated cells, after in vivo challenge with NPY. All together suggest that NPY is expressed in immune tissues and modulates the immune response in teleost fish.     

Mutations I117V and I117M and oseltamivir sensitivity of pandemic (H1N1) 2009 viruses

Analysis of mutations I117V and I117M in the neuraminidase of influenza A pandemic (H1N1) 2009 viruses showed that I117V confers a mild reduction in oseltamivir sensitivity and has a synergistic effect of further increasing resistance when combined with H275Y. Contrary to recent reports, the I117M mutation does not alter oseltamivir sensitivity.     

Comparisons of oseltamivir‐resistant (H275Y) and concurrent oseltamivir‐susceptible seasonal influenza A(H1N1) virus infections in hospitalized adults, 2008–2009

In an observational cohort study, we found that adults hospitalized for oseltamivir‐resistant (H275Y) seasonal H1N1 influenza (n = 46) were older than those infected with oseltamivir‐susceptible strains (n = 31) [74(IQR 59–83) versus 64(IQR 48–76) years; P = 0·045], and most had major comorbidities (78% versus 65%). Disease severity and clinical outcomes were comparable between the two groups: radiographic pneumonia 40–42%, supplemental oxygen use 47–48%, critical illness 11–13%, median duration of hospitalization 5–6 days, death rate 6–9%. Failure to receive effective antiviral therapy was associated with progression to critical illness (23% versus 0%, P = 0·016) and death (20% versus 0%, P = 0·033) in hospitalized patients with seasonal H1N1 influenza.