复方辛伐他汀烟酸缓释片中烟酸在不同释放介质中的释放度研究

目的研究辛伐他汀烟酸缓释片在不同释放介质中烟酸的释放度,分析其在体外的释放行为。方法用UV法测定自制与进口辛伐他汀烟酸缓释片在四种不同介质中的烟酸释放情况,并对其释放模型和f2相似因子进行比较。结果自制和进口缓释片的烟酸体外释放度符合Ritger-Peppas方程,在四种介质中方程拟合的n值均在0.45～0.89之间,说明该药物释放是药物扩散和骨架溶蚀共同作用的。与参比制剂相比,自制缓释片在水、0.1 mol/L盐酸、pH4.5醋酸盐缓冲液及pH 6.8磷酸盐缓冲液释放介质中,f2值分别为67.59、80.24、67.27和65.57,均大于50。结论自制制剂与进口制剂的缓释部分体外释放行为相似。     

A comparison of the nutrient content of uncooked and cooked lean from New Zealand beef and lamb

The composition in terms of proximate analysis, cholesterol, vitamins, minerals, and fatty acids of the lean tissue of 17 beef cuts and 18 lamb cuts was determined on within-cut composite samples (each containing lean tissue from at least 7 animals), following the knife-separation of raw and cooked cuts into lean, fat, and bone. Composite lean samples for 4 beef cuts and 4 lamb cuts were also analysed for amino-acid composition. For analysis, different cuts were the experimental unit as individual animal data were not available. The composition of lean from beef and lamb was shown to be highly desirable with a high nutrient density (mg/kJ) for many nutrients. Although lean from beef and lamb were very similar in many respects, several significant differences were detected. Changes in composition with cooking were largely eliminated when considered on a dry-matter basis, but proportions of the n-3 and n-6 polyunsaturated fatty acids increased with cooking (P < 0.05). The amino acid composition was similar for lean from beef and lamb but showed small deviations from recommended patterns for human nutrition with branched chain amino acids being limiting.     

Pharmacological effects of lipid-lowering drugs on circulating adipokines

The cardioprotective effects of lipid-lowering drugs have been primarily attributed to their effects on blood lipid metabolism. However, emerging evidence indicates that lipid-lowering drugs also modulate the synthesis and secretion of adipose tissue-secreted proteins referred to as adipokines. Adipokines influence energy homeostasis and metabolism and have also been shown to modulate the vascular inflammatory cascade. The purpose of this review will be to examine the reported effects of commonly used lipid-lowering drugs (statins, fibrates, niacin and omega-3-fatty acids) on the circulating concentrations of leptin, adiponectin, tumor necrosis-factor-α (TNF-α), Retinol binding protein 4 (RBP4) and resistin. Overall, the lipid-lowering drugs reviewed have minimal effects on leptin and resistin concentrations.Conversely, circulating adiponectin concentrations are consistently increased by each lipid-lowering drug reviewed with the greatest effects produced by niacin. Studies that have examined the effects of statins, niacin and omega-3-fatty acids on TNF-α demonstrate that these agents have little effect on circulating TNF-α concentrations. Niacin and fibrates appear to lower RBP4 but not resistin concentrations. The results of the available studies suggest that a strong relationship exists between pharmacological reductions in blood lipids and adiponectin that is not obvious for other adipokines reviewed.     

寻常性痤疮与功能性消化不良的关系初探

目的：观察痤疮患者伴随的消化不良症状及药理剂量的烟酸、锌及其他维生素对轻、中、重度（pillsbury分级法）寻常性痤疮的治疗效果。方法：将176例轻、中、重度寻常性痤疮患者随机分为两组：治疗组,口服烟酸、锌、VitB12、VitB6、VitE、叶酸等,不能耐受皮肤发红者用烟酰胺替代;对照组,口服乙酰螺旋霉素片、VitB12、VitB6、VitE、叶酸、锌口服,抗菌素用3天。门诊记录患者伴随症状,两组疗程均为4周。治疗结束后观察治疗组中继续烟酸治疗的患者与停药患者的复发情况。结果：93.2%以上的痤疮患者伴有不同程度的消化道症状,68.5%的患者伴有明显的功能性消化不良。治疗组和对照组有效率分别为93.26%和36.36%,治疗组有效人数明显高于对照组,P〈0.01。随访停药2周后的患者复发率明显高于继续用药的患者,P〈0.05。结论：烟酸治疗寻常性痤疮具有良好疗效,长期大剂量使用的目的不仅在于治疗和预防痤疮,还在于治疗痤疮伴随的抑郁症、消化不良等并发症。观察结果提示痤疮患者存在烟酸缺乏,特别是女性患者。痤疮患者伴随的各种消化道症状应该考虑到很可能是由于烟酸缺乏导致的能量代谢障碍,并由此造成胃肠蠕动及吸收功能障碍,而非仅仅由于食物造成的功能性消化不良,这有待于进一步研究。     

蛋白激酶B和丝裂原活化蛋白激酶在烟酸保护的HaCaT细胞抵抗中波紫外线损伤中的作用

目的 探讨烟酸保护由UVB诱导的角质形成细胞损伤的胞内信号传导分子机制。 方法 UVB照射和烟酸处理HaCaT细胞,TUNEL法检测细胞凋亡,Western印迹检测蛋白激酶B（Akt）/丝裂原活化蛋白激酶（MAPK）通路相关蛋白Akt、P38、JNK、ERK1/2的磷酸化水平变化。ELISA检测细胞分泌内皮素1（ET-1）及碱性成纤维细胞生长因子（bFGF）的水平。结果 Western印迹结果表明,UVB照射和烟酸处理HaCaT细胞后,p-Akt、p-P38、p-JNK、p-ERK1/2蛋白在60 min内都显著激活（P < 0.01）。烟酸预处理后的HaCaT细胞再经UVB照射,可以发现p-Akt、p-P38、p-ERK1/2信号分子在2 h内激活更显著（P < 0.01）。３个抑制剂加UVB照射组较3个单独抑制剂组ET-1、bFGF表达降低,差异均有统计学意义,其中LY294002组、SB203580组ET-1、bFGF水平最低;烟酸预保护的抑制剂处理组HaCaT细胞在UVB照射后,LY294002和U0126组没有出现ET-1、bFGF水平回升,SB203580组bFGF水平出现回升。结论　Akt信号分子在烟酸保护的HaCaT细胞抵抗UVB损伤中起一定的调控作用。     

Evaluation of adverse events reported in Traditional Iranian Medicine following administration of aqueous extract of Herba Portulacae Oleraceae seed

Objective

To find scientific reasons for adverse events reported in traditional Iranian medicine (TIM) following administration of aqueous extract of Portulaca oleracea L. seed including itching and tingling of whole body, tachycardia, anxiety, dyspnea and severe nausea.

Methods

Electronic databases including PubMed, Scopus, and Web of Science were searched up to April 2013 to find papers focused on phytochemistry and biological activities of this plant.

Results

Among chemical constituents present in Portulaca oleracea, catecholamines, adenosine and niacin can cause adverse events similar to those reported in TIM.

Conclusion

Because of the short duration of action of adenosine, catecholamines and niacin seems to be the major role in appearance of adverse events reported in TIM for Portula oleracea seed. Mechanisms with consideration of receptor types and pharmacokinetics of catecholamine and niacin are warranted to confirm this hypothesis.     

Effects of An Oral Mixture Containing Glycine,Glutamine and Niacin on Memory,GH and IGF-I Secretion in Middle-aged and Elderly Subjects

Abstract

Aging is associated with declining activity of the growth hormone-insulin-like growth factor-I (GH-IGF-I) axis and with a decrease in cognitive function. The stimulatory effect of an orally administered nutritional supplement, mainly containing glycine, glutamine and niacin on the GH-IGF-I axis and on mood and cognition was investigated. Forty-two healthy subjects (14 men and 28 women, aged 40-76 years) were enrolled in a randomised, double blind, placebo-controlled trial. They received 5 g of a nutritional supplement or placebo, twice daily orally for a period of 3 weeks. At baseline and after 3 weeks, blood was collected for measurement of serum GH and IGF-I levels and mood and cognitive function were tested. The nutritional supplement ingestion for 3 weeks was found to increase serum GH levels with 70% relatively to placebo, whereas circulating IGF-I levels did not change. Mean GH (±SD) increased in this group from 3.23 (±4.78) to 4.67 mU/l (±5.27) (p=0.03). GH increase was not associated with improvement in mood or memory. Correlation analyses, however, revealed that individual increases in IGF-I, but not GH, were associated with improved memory and vigour. It is concluded that an oral mixture of glycine, glutamine and niacin can enhance GH secretion in healthy middle-aged and elderly subjects.     

烟酸对实验性动脉粥样硬化兔主动脉斑块形成和MK2表达的影响

目的探讨烟酸对动脉粥样硬化斑块形成及动脉壁MK2 mRNA表达的影响。方法 16只雄性新西兰大白兔给予高脂饮食8周后,随机分为高脂血症组(n=8)和烟酸组(n=8),高脂血症组继续饲以高脂饲料6周,烟酸组在高脂饮食基础上给予烟酸[200 mg/(kg.d)]6周。另选8只兔给予普通饮食14周作为正常对照组。14周末处死动物进行主动脉病理学检测,采用实时定量PCR检测各组兔主动脉壁MK2 mRNA的表达。结果与正常对照组相比,高脂血症组总胆固醇和低密度脂蛋白胆固醇水平明显升高,主动脉内膜厚度和斑块面积显著增加,MK2 mRNA表达显著增加(P0.01)。与高脂血症组相比,烟酸组总胆固醇和低密度脂蛋白胆固醇水平显著降低,高密度脂蛋白胆固醇水平升高,主动脉内膜厚度和斑块面积显著减少,MK2 mRNA表达也显著减少(P均0.01)。MK2 mRNA表达量与动脉粥样硬化斑块面积(r=0.919,P0.01)和内膜厚度(r=0.863,P0.01)呈正相关。结论烟酸抗动脉粥样硬化作用除与其降脂作用有关外,还可能与其降低MK2 mRNA水平有关。     

Chronic niacin overload may be involved in the increased prevalence of obesity in US children

AIM: To investigate nicotinamide’s action on glucose metabolism, and the association between niacin consumption and obesity prevalence. METHODS: Dynamic nicotinamide’s effect on plasma hydrogen peroxide and glucose metabolism was in- vestigated using oral glucose tolerance tests with or without nicotinamide in the same five healthy subjects.Lag-regression analysis was used to examine the association between the niacin consumption and the obesity prevalence among US children using the data from the Economic ...