分子吸收光度法测定万寿菊中代森锰锌残留量

目的:采用分子吸收光度法测定万寿菊中代森锰锌残留。方法:通过蒸馏和溶液吸收实验装置,氯化亚锡催化,二乙基二硫代氨基甲酸钠分解定量产生二硫化碳气体,通过浓硫酸脱氧脱水,氢氧化钾的甲醇液吸收,用分光光度法在304 nm波长处测定其标准曲线。代森锰锌以平均相对分子质量333计,可通过平均相对分子质量计算出代谢锰锌的含量。结果:万寿菊中添加浓度为10 mg.kg-1和20 mg.kg-1(以二硫化碳计)的回收率(n=5)分别为95.9%和93.2%,RSD分别为4.8%和3.7%;最低检测限为2 mg.kg-1。结论:该方法操作简单,灵敏度高,适合大批量样品的检测。     

Phase Transformation after Heat Treatment of Cr-Ni Stainless Steel Powder for 3D Printing

Today, Ni-Cr steel is used for advanced applications in the high-temperature and electrical industries, medical equipment, food industry, agriculture and is applied in food and beverage packaging and kitchenware, automotive or mesh. A study of input steel powder from various stages of the recycling process intended for 3D printing was conducted. In addition to the precise evaluation of the morphology, particle size and composition of the powders used for laser 3D printing, special testing and evaluation of the heat-treated powders were carried out. Heat treatment up to 950 °C in an air atmosphere revealed the properties of powders that can appear during laser sintering. The powders in the oxidizing atmosphere change the phase composition and the original FeNiCr stainless steel changes to a two-phase system of Fe₃Ni and Cr₂O₃, as evaluated by X-ray diffraction analysis. Observation of the morphology showed the separation of the oxidic phase in the sense of a brittle shell. The inner part of the powder particle is a porous compact core. The particle size is generally reduced due to the peeling of the oxide shell. This effect can be critical to 3D printing processing, causing defects on the printed parts, as well as reducing the usability of the precursor powder and can also change the properties of the printed part.     

Elucidation of Anti-Hypertensive Mechanism by a Novel Lactobacillus rhamnosus AC1 Fermented Soymilk in the Deoxycorticosterone Acetate-Salt Hypertensive Rats

Dietary intake of fermented soymilk is associated with hypotensive effects, but the mechanisms involved have not been fully elucidated. We investigated the anti-hypertensive effects of soymilk fermented by L. rhamnosus AC1 on DOCA-salt hypertension from the point of view of oxidative stress, inflammatory response and alteration of the gut microbiome. The antioxidant assays in vitro indicated the ethanol extract (EE) of L. rhamnosus AC1 fermented soymilk showed better antioxidative effects than the water extract (WE). Those extracts displayed a hypotensive effect using a tail-cuff approach to measuring blood pressure and improved nitric oxide (NO), angiotensin II (Ang II), tumor necrosis factor-α (TNF-α) and interleukin factor-6 (IL-6) on DOCA-salt hypertensive rats. Furthermore, cardiac and renal fibrosis were attenuated by those extracts. The gut microbiota analysis revealed that they significantly reduced the abundance of phylum Proteobacteria, its family Enterobacteriaceae and genus Escherichia-Shigella. Moreover, metabolomic profiling revealed several potential gut microbiota-related metabolites which appeared to involve in the development and recovery of hypertension. In conclusion, fermented soymilk is a promising nutritional intervention strategy to improve hypertension via reducing inflammation and reverting dysbiotic microbiota.     

重组人乳头瘤病毒11型L1蛋白在昆虫细胞sf 9中的表达条件优化研究

目的 确定利用昆虫细胞一杆状病毒表达系统表达重组人乳头瘤病毒11型L1蛋白(HPV11 L1)的最适表达条件.方法 通过间接免疫荧光法鉴定目的蛋白表达情况;用蛋白印迹法(Western blot)确定在不同感染复数(MOI)、不同表达时间条件下目的蛋白的最适表达条件.结果 当sf9细胞密度为2.0×106/ml时,以MOI值为2.0的重组杆状病毒接种,悬浮表达96 h收获为最适表达条件.结论 确定了目的蛋白的最适表达条件,为进一步大量表达及纯化提供参考.     

Immobilization effect of Ruta graveolens L. on human sperm: a new hope for male contraception

AIM OF THE STUDY: Contraceptive plants which were introduced by folk in traditional remedies are investigated worldwide. In this study, the contraceptive effects of Ruta graveolens L., which has been mentioned for male contraceptive in Iranian traditional folk medicine, was experimented on human sperm. MATERIALS AND METHODS: Different doses of lyophilized aqueous extract of Ruta graveolens L. were added to an amount of fresh semen, containing 10(6) cells in a 1:1 volumic ratio. Motility and viability of cells, DNA status, mitochondrial activity and sperm revival tests were carried out. RESULTS: The sperm immobilization effects of the extract appeared immediately in a does-dependent manner and 100% of the sperms became immotile at a concentration of 100mg/ml but other parameters were intact. After washing the sperms, motility was returned in 30.8+/-3.2% of the sperms, besides coiled tails in 38.6+/-5.5% of the treated cells, in comparison to 12.5+/-2.0% of the control group (p=0.001). The part of the extract, responsible for immobilization of the sperms was stable upon boiling. CONCLUSIONS: As the cells were alive and immotile, probably some ionic currents are blocked by a thermostable component of the plant which can be promising as a new male channel blocker contraceptive.     

Endothelium-independent relaxation and contraction of rat aorta induced by ethyl acetate extract from leaves of Morus alba (L.)

Aim of the study

Based on screening for vasoactive traditional Chinese medicinal herbs, the present study was performed to investigate the vasoactive effects of an ethyl acetate extract from leaves of Morus alba (L.) (ELM) on rat thoracic aorta and the mechanisms underlying these effects.

Materials and methods

Isolated rat thoracic rings were mounted in an organ bath system and the effects of ELM on their responses were evaluated.

Results

ELM (0.125–32.000 g/l) induced a concentration-dependent relaxation (P < 0.01 vs. control) both in endothelium-intact and -denuded aortas precontracted by high K⁺ (6 × 10⁻² M) or 10⁻⁶ M phenylephrine (PE). In endothelium-denuded aortas, ELM at the EC₅₀ concentration reduced Ca²⁺-induced contraction (P < 0.01 vs. control) after PE or KCl had generated a stable contraction in Ca²⁺-free solution. And after incubation with verapamil, ELM induced contraction in endothelium-denuded aortas precontracted by PE (P < 0.01 vs. control); this was abolished by ruthenium red (P < 0.01 vs. ELM-treated endothelium-denuded group; P > 0.05 vs. control), but not by heparin (P > 0.01 vs. ELM-treated endothelium-denuded group; P < 0.01 vs. control).

Conclusions

The results showed that ELM had dual vasoactive effects, and the relaxation was greater than the contraction. The relaxation was mediated by inhibition of voltage- and receptor-dependent Ca²⁺ channels in vascular smooth muscle cells, while the contraction occurred via activation of ryanodine receptors in the sarcoplasmic reticulum.     

A review of the taxonomy, ethnobotany, chemistry and pharmacology of Sutherlandia frutescens (Fabaceae)

Sutherlandia frutescens (tribe Galegeae, Fabaceae), a popular plant in traditional medicine, is indigenous to South Africa, Lesotho, southern Namibia and southeastern Botswana. It is chemically, genetically and geographically extremely variable and has been divided into three subspecies and several regional forms. A second species, Sutherlandia tomentosa, is localized along the Cape coast. Sutherlandia is sometimes treated as part of the genus Lessertia. There are numerous vernacular names and a wide diversity of uses, including poor appetite, indigestion, stomach complaints, dysentery, colds, influenza, kidney conditions, fever, diabetes, internal cancers, uterine troubles, liver conditions, backache, rheumatoid arthritis, urinary tract infections, stress and anxiety, dropsy and heart failure. Notable is the use as a bitter tonic ("blood purifier"), anti-stress medication ('musa-pelo) and, at least since 1895, specifically as a cancer tonic (both as treatment and as prophylaxis). Externally it is applied to haemorrhoids, inflamed wounds and eye infections. Recent in vitro and in vivo studies have shown antiproliferative, anti-HIV, anti-diabetic, anti-inflammatory, analgesic, antibacterial, anti-stress, anticonvulsant and antithrombotic activities. Aqueous extracts often differ in activity from organic solvent extracts. The presence of high levels of free amino acids, non-protein amino acids such as canavanine and GABA, the cyclitol pinitol, flavonols and triterpenes (including SU1, a cycloartane-type triterpene saponin) provide plausible hypotheses on how these compounds, individually or collectively, may be responsible for the reputed efficacy in a wide range of ailments. Results of animal studies, as well as a phase I clinical study, have shown no indications of toxicity. Sufficient preclinical data are now available to justify controlled clinical studies.     

Bioassay-guided isolation of anti-inflammatory and antinociceptive principles from a folk remedy, Rhododendron ponticum L. leaves

Ethnopharmacological relevance: Rhododendron ponticum L. (Ericaceae) is used for the treatment of inflammatory diseases and to alleviate rheumatic pain and against toothache in Turkish traditional medicine.     

Astragaloside IV attenuates lipolysis and improves insulin resistance induced by TNFalpha in 3T3-L1 adipocytes

Increased circulating free fatty acid (FFA) concentrations have been demonstrated to potentially link obesity, insulin resistance and cardiovascular diseases. Astragaloside IV (AS-IV) is a saponin which is widely used in traditional Chinese medicine to treat type 2 diabetes and cardiovascular diseases. The purpose of the present study was to examine the effects of AS-IV on the lipolysis and insulin resistance induced by tumor necrosis factor-alpha (TNFalpha) in cultured 3T3-L1 adipocytes. TNFalpha promotes lipolysis in mammal adipocytes via the mitogen activated protein kinase (MAPK) family resulting in reduced expression/function of perilipin. Application of AS-IV inhibited TNFalpha-induced accelerated lipolysis in a dose-dependent manner, which was compatible with suppressed phosphorylation of ERK1/2 and reversed the downregulation of perilipin. Moreover, TNFalpha induced downregulation of key enzymes in lipogenesis, including LPL, FAS and GPAT, were also attenuated by AS-IV. Further studies showed that AS-IV improved TNFalpha-induced insulin resistance in 3T3-L1 adipocytes. This study provides the first direct evidence of the antilipolytic action of AS-IV in adipocytes, which may allow this agent to decrease the circulating FFA levels, thus increase insulin sensitivity and treat cardiovascular diseases.     

Dietary red chilli (Capsicum frutescens L.) is insulinotropic rather than hypoglycemic in type 2 diabetes model of rats

The present study was conducted to clarify whether a low or a high, but tolerable, dietary dose of red chilli (RC) can ameliorate the diabetes related complications in a high-fat (HF) diet-fed streptozotocin (STZ)-induced type 2 diabetes model of rats. Five-week-old male Sprague Dawley rats were fed a HF diet for 2 weeks then randomly divided into four groups namely: normal control (NC), diabetic control (DBC), red chilli low (RCL, 0.5%) and red chilli high (RCH, 2.0%) groups. Diabetes was induced by an intraperitoneal (i.p.) injection of STZ (40 mg/kg BW) in all groups except the NC group. After 4 weeks feeding of experimental diets, the fasting blood glucose concentrations in both RC fed groups were not significantly different. The serum insulin concentration was significantly (p < 0.05) increased in the RCH group compared with the DBC and RCL groups. Blood HbA1c, liver weight, liver glycogen and serum lipids were not influenced by the feeding of RC-containing diets. The data of this study suggest that 2% dietary RC is insulinotropic rather than hypoglycemic at least in this experimental condition.