Production,composition and toxicology studies of Enzogenol® Pinus radiata bark extract

Enzogenol® pine bark extract is a dietary supplement and food ingredient produced by water extraction of Pinus radiata. We present production method, composition, and safety data from rat and dog toxicological and human clinical studies. The dry powder contains proanthocyanidins (>80%), taxifolin (1–2%), other flavonoids and phenolic acids (up to 8%), and carbohydrates (5–10%). Reverse mutation assays showed lack of mutagenic activity. Single and 14-day repeat dosing in rats and dogs had no influence on body weight, feed consumption, blood chemistry, and haematology at any dose level. There were no treatment related findings on gross and detailed necroscopy, organ weights, organ weight ratios and histology. The only adverse events were emesis and diarrhoea in dogs occurring mainly in un-fed condition and at the highest dose level in a total of 18% of applications. The MTD and NOAEL in the present rat and dog studies were 2500 and 750 mg/kg/day, respectively. Consumption of 480 mg/day for 6 months and 960 mg/day for 5 weeks in two human studies showed Enzogenol® had no adverse influence on liver and kidney function, haematology, and did not cause any adverse events. Our studies indicate lack of toxicity of Enzogenol® and support safe use as a food ingredient.     

Novel haemoglobin mutation (α127Lys → Glu) increases oxygen affinity and has a minor effect on haptoglobin binding

Objectives

To determine if a new haemoglobin (Hb) variant was the underlying cause of erythrocytosis in a subject with a high apparent HbA₁c.

Design and method

Haemolysate was analysed by ESI MS, and individual components purified by ion exchange and reverse phase chromatography. Peptide mapping was used to pinpoint the substitution and DNA sequencing to confirm the precise mutation. Oxygen affinity was measured and relative haptoglobin (Hp) binding estimated.

Results

Intact protein analysis and peptide mapping suggested a mutation in peptide α13 and DNA sequencing confirmed a novel α127Lys → Glu substitution in the α 2 gene. The abnormal Hb had a significantly higher O₂ affinity (5.8 mm Hg) than HbA (12.4 mm Hg). In addition the mutation caused a small but significant decrease in Hp binding.

Conclusion

Molecular models show that the side chain of α127Lys stabilises the T structure of deoxy Hb and that mutation to Glu would favour conversion to the high affinity R state. Notwithstanding this and the demonstrated high affinity, there was only a small increase in RBCs, Hb concentration and PCV in other female carriers of the mutation. The absence of a significant phenotype of erythrocytosis is most probably due to the low level (19%) of the variant.     

应用HPLC-ESI-IT-MS~n法推定硫酸西索米星中有关物质的结构

目的:建立HPLC-ESI-IT-MSn方法,研究硫酸西索米星的杂质谱。方法:采用Agilent 1100 LC/MSD Trap液质联用仪,采用Gemini NX C18(4.6 mm×150 mm,5μm)色谱柱,以水-氨水-冰醋酸(96∶3.6∶0.4)为流动相A,甲醇为流动相B,梯度洗脱,流速1 mL.min-1;质谱检测器采用ESI离子源,正离子检测,离子源温度为350℃,雾化室压力为275.8 kPa,干燥气流速为9 L.min-1;检出杂质结构的鉴定方法根据有无杂质对照品而异:对于有对照品的杂质,通过比较其与对照品的色谱和质谱行为来确定结构;对于无对照品的未知杂质,则以已知结构物质如西索米星、奈替米星等为模型,通过分析已知物与未知杂质多级质谱行为的异同性推定其结构。结果:硫酸西索米星原料中检出16个有关物质,其中14个物质的结构得到归属。结论:本文建立的HPLC-ESI-IT-MSn方法及研究结果对硫酸西索米星的质量控制和工艺评价具有参考意义。     

Reversible time-dependent inhibition of cytochrome P450 enzymes by duloxetine and inertness of its thiophene ring towards bioactivation

Duloxetine is a selective serotonin-norepinephrine reuptake inhibitor (SNRI) approved to treat major depressive disorder and diabetic peripheral neuropathic pain. It is known to cause hepatotoxicity, in some cases leading to death. It has been reported that duloxetine causes time-dependent inhibition (TDI) of CYP1A2, CYP2B6, CYP2C19 and CYP3A4/5; but the nature of these TDI (whether reversible or irreversible) is not known. Irreversible TDI can cause clinically significant drug-drug interactions and also immune-mediated hepatotoxicity. Structurally, duloxetine possesses several toxicophores, i.e. the naphthyl and thiophene rings. It has been reported that the naphthyl ring undergoes epoxidation and was subsequently adducted to glutathione, but bioactivation related to the thiophene ring has not been completely elucidated. In this paper, the potential of duloxetine in causing irreversible TDI and generating reactive metabolites was investigated. Human liver microsomal assays demonstrated that duloxetine did not cause irreversible TDI of CYP1A2, CYP2B6, CYP2D6, CYP2C19 and CYP3A4/5. Subsequently, reactive metabolite trapping assays using soft nucleophiles (glutathione and glutathione ethyl ester) revealed a previously reported adduct at the naphthyl ring of duloxetine but not at the thiophene ring. Trapping assays utilizing a hard nucleophile (semicarbazide) did not demonstrate adducts with the thiophene ring, indicating an absence of thiophene ring opening. The hepatotoxicity of duloxetine is possibly not related to the irreversible TDI of CYP450 or the bioactivation of its thiophene moiety, but might be due to the epoxidation of its naphthyl ring.     

Benzylidenemalononitrile compounds as activators of cell resistance to oxidative stress and modulators of multiple signaling pathways. A structure-activity relationship study

Benzylidenemalononitrile (BMN) tyrphostins are well known as potent tyrosine kinase inhibitors. Moreover, in recent years it has been recognized that members of the tyrphostin family possess additional biological activities independent of their ability to inhibit protein tyrosine kinases. In this study, we examined the relationship between the structure of 49 BMNs and related compounds, and their capacity to induce heme oxygenase 1 (HO-1) gene expression in U937 human monocytic cells, to activate upstream signaling pathways and to protect cells against menadione-induced oxidative stress. It was found that the electron-withdrawing (NO₂, CN, halogen) groups in BMN molecules and double meta-MeO substituents increased the HO-1 gene induction, while the electron-donating groups in ortho/para position (OH, MeO and N-morpholino) significantly decreased it. The magnitude of activation of c-Jun, Nrf2, p38 MAPK, and p70S6K correlated with specific substitution patterns in the BMN structure. BMN-dependent maximal up-regulation of HO-1 required parallel increase in Nrf2 and phospho-c-Jun cellular levels. Liquid chromatography mass spectrometry (LC–MS) analysis revealed that BMNs can generate conjugates with one or two glutathione equivalent(s). This study supports the hypothesis that BMNs induce the expression of protective genes by alkylating sensitive cysteine residues of regulatory factors.     

Interaction of packaging motor with the polymerase complex of dsRNA bacteriophage

Many viruses employ molecular motors to package their genomes into preformed empty capsids (procapsids). In dsRNA bacteriophages the packaging motor is a hexameric ATPase P4, which is an integral part of the multisubunit procapsid. Structural and biochemical studies revealed a plausible RNA-translocation mechanism for the isolated hexamer. However, little is known about the structure and regulation of the hexamer within the procapsid. Here we use hydrogen-deuterium exchange and mass spectrometry to delineate the interactions of the P4 hexamer with the bacteriophage phi12 procapsid. P4 associates with the procapsid via its C-terminal face. The interactions also stabilize subunit interfaces within the hexamer. The conformation of the virus-bound hexamer is more stable than the hexamer in solution, which is prone to spontaneous ring openings. We propose that the stabilization within the viral capsid increases the packaging processivity and confers selectivity during RNA loading.     

Electromagnetic source imaging using simultaneous scalp EEG and intracranial EEG: An emerging tool for interacting with pathological brain networks

Objective

The goal of this study is to investigate the performance, merits and limitations of source imaging using intracranial EEG (iEEG) recordings and to compare its accuracy to the results of EEG source imaging. Accuracy in this study, is measured both by determining the location and inter-nodal connectivity of underlying brain networks.

Toxicology effects of Morning Glory Seed in rat: A metabonomic method for profiling of urine metabolic changes

Ethnopharmacological relevance

Morning Glory Seed (MGS) is a valuable traditional Chinese medicine which is widely used for the treatment of edema, ascites, hydroncus, simple obesity, lung fever and ardent fever. In recent years, long-term exposure to Morning Glory Seed (MGS) has shown to pose progressive renal damage in clinical practice. We hypothesize that changes in metabolic profile could have occurred before symptoms were observed, which may allow early treatment.

Aim of the study

To investigate the metabolic changes caused by Morning Glory Seed-induced renal damage.

Method

Metabonomics method was used for chronic toxicology study of MGS in Wistar rats. With a therapeutic dose, the model rats were orally administered the extract of MGS for 10 weeks continuously. The urine samples of model and control rats were collected in various time-points and the endogenous metabolites were analyzed by ultraperformance liquid chromatography coupled with mass spectrometry. The identification of all the potential biomarkers was performed using reference standard by comparing their mass spectra, MS/MS fragmentation and retention time. Furthermore, histopathology and clinical chemistry studies were carried out to ensure the success of MGS-induced nephrotoxicity model.

Results

The difference in metabolic profiles between the control and the dosed rats was well observed by the principal component analysis (PCA) of the MS spectra. Significant changes of 12 metabolite biomarkers were detected in the rat urine samples. Metabonomics method could discriminate the model rats from the control rats in 2nd, 6th and10th week respectively before serious organic damage of kidney was found in 10th week by histopathology method.

Conclusion

We believe that metabolic profiling may act as a preclinical protocol for MGS exposure before symptoms are observed.     

Differential proteome analysis of diabetes mellitus type 2 and its pathophysiological complications

The prevalence of Diabetes Mellitus Type 2 (DM 2) is increasing every passing year due to some global changes in lifestyles of people. The exact underlying mechanisms of the progression of this disease are not yet known. However recent advances in the combined omics more particularly in proteomics and genomics have opened a gateway towards the understanding of predetermined genetic factors, progression, complications and treatment of this disease. Here we shall review the recent advances in proteomics that have led to an early and better diagnostic approaches in controlling DM 2 more importantly the comparison of structural and functional protein biomarkers that are modified in the diseased state. By applying these advanced and promising proteomic strategies with bioinformatics applications and bio-statistical tools the prevalence of DM 2 and its associated disorders i-e nephropathy and retinopathy are expected to be controlled.     

基于ESI的临床医学学科热门论文分布及其研究热点

选用ESI数据库,对临床医学热门论文国家及期刊分布进行文献计量分析,对引用排名前62的论文进行共被引分析。结果表明,美国和《新英格兰医学杂志》在临床医学领域的热门论文最多。心血管疾病的预防和控制、肿瘤、丙型肝炎以及心血管疾病药物临床试验是研究热点。