青霉素、硫酸庆大霉素对红剑鱼、孔雀鱼和食蚊鱼的急性毒性实验

目的 :观察青霉素、硫酸庆大霉素对红剑鱼、孔雀鱼和食蚊鱼的急性毒性影响 ,以探讨红剑鱼、孔雀鱼和食蚊鱼作为水生实验动物的可行性及对药物急性毒性的检测效果。方法 :用水毒理学方法测定它们对三种鱼类的 2 4hLC50 。结果 :青霉素对红剑鱼、孔雀鱼和食蚊鱼的急性毒性观察结果 ,2 4hLC50 值分别为 2 83.0 6mg/L、2 79.92mg/L、2 89.4 4mg/L ;硫酸庆大霉素对红剑鱼、孔雀鱼和食蚊鱼的急性毒性观察结果 ,2 4hLC50 值分别为 2 95 .97ug/L、2 73.74ug/L、30 9.0 3ug/L。结论 :红剑鱼、孔雀鱼和食蚊鱼可作为急性毒性的试验材料。     

大鼠长期服苯妥英锌或苯妥英钠对体内锌铜代谢的影响

本文用原子吸收分光光度法测定了大鼠分别服用苯妥英锌和苯妥英钠13周后(每天剂量为12mg/kg体重),肝脏、全脑、齿龈和血清锌铜的含量。苯妥英锌使齿龈和肝脏锌分别增高80％和49％,全脑和血清锌分别降低39％和35％,而苯妥英钠使齿龈和肝脏锌分别降低70％和28％,血清锌增高41％。两药均使全脑和齿龈铜降低。     

Reconsidering the Tolerable Upper Levels of Zinc Intake among Infants and Young Children: A Systematic Review of the Available Evidence

Safe upper levels (UL) of zinc intake for children were established based on either (1) limited data from just one study among children or (2) extrapolations from studies in adults. Resulting ULs are less than amounts of zinc consumed by children in many studies that reported benefits of zinc interventions, and usual dietary zinc intakes often exceed the UL, with no apparent adverse effects. Therefore, existing ULs may be too low. We conducted a systematic bibliographic review of studies among preadolescent children, in which (1) additional zinc was provided vs. no additional zinc provided, and (2) the effect of zinc on serum or plasma copper, ceruloplasmin, ferritin, transferrin receptor, lipids, or hemoglobin or erythrocyte super-oxide dismutase were assessed. We extracted data from 44 relevant studies with 141 comparisons. Meta-analyses found no significant overall effect of providing additional zinc, except for a significant negative effect on ferritin (p = 0.001), albeit not consistent in relation to the zinc dose. Interpretation is complicated by the significant heterogeneity of results and uncertainties regarding the physiological and clinical significance of outcomes. Current zinc ULs should be reassessed and potentially revised using data now available for preadolescent children and considering challenges regarding interpretation of results.     

Sulfate Freeze–Thaw Resistance of Magnesium Potassium Phosphate Cement Mortar

Concrete facilities in the severe-cold areas of western China (salt lake environments and heavy saline soils) are seriously damaged by the multiple corrosion effects of freeze–thaw cycles and sulfate corrosion. Magnesium phosphate cement (MPC) cement-based material has become an ideal concrete structural component because of its superior performance. Because concrete structural repair materials are used in heavy-corrosion environments, their durability in those environments should also be considered. Regarding the salt-freezing resistance of MPC, the existing studies have all used a NaCl solution as the heat transfer medium. In addition to chlorine salt, sulfate, especially Na₂SO₄, is also common in typical use environments such as oceans, salt lakes, and groundwater. To evaluate the sulfate freeze–thaw resistance of potassium magnesium phosphate cement (MKPC) mortar, in this study the strength development, weight loss, and water absorption of MKPC mortar specimens subjected to different freeze–thaw cycles were tested and compared with those for Portland cement (P.O) mortar specimens of the same strength grade. The results showed that the P.O mortar specimen completely lost its strength after 75 cycles of rapid water freezing and thawing and 50 cycles of sodium sulfate solution (5%) freezing and thawing. However, the residual strength rating of the MKPC mortar specimen after 75 cycles of water freezing and thawing and 100 cycles of sodium sulfate solution freezing and thawing was higher than 75%. After 50 rapid freeze–thaw cycles in water and a 5% Na₂SO₄ solution, the P.O mortar specimen’s mass loss exceeded the 5% failure standard, whereas the mass loss of the MKPC mortar specimens was much less than 5%. Before the freeze–thaw cycles, the water absorption of the P.O mortar specimen was close to 8 times that of the MKPC mortar specimen, and after 50 water freeze–thaw cycles and 25 sulfate solution freeze–thaw cycles, the water absorption reached 4.88% and 5.68%, respectively. However, after 225 freeze–thaw cycles in water and the sulfate solution, the water absorption rates of MKPC mortar specimens were 2.91% and 2.51% respectively. The test and analysis results show that the freeze–thaw resistance of MKPC mortar was much higher than that of Portland cement mortar specimens. Those results provide a prerequisite for applying and expanding the use of MKPC-based materials in severe-cold areas of western China (salt lake and heavily saline soil environments).     

Controlling the Wettability of ZnO Thin Films by Spray Pyrolysis for Photocatalytic Applications

Herein, we synthesized the zinc oxide (ZnO) thin films (TFs) deposited on glass substrates via spray pyrolysis (SP) to prepare self-cleaning glass. Various process parameters were used to optimize photocatalytic performance. Substrates were coated at room temperature (RT) and 250 °C with a 1 mL or 2 mL ZnO solution while maintaining a distance from the spray gun to the substrate of 20 cm or 30 cm. Several characterization techniques, i.e., XRD, SEM, AFM, and UV–Vis were used to determine the structural, morphological, and optical characteristics of the prepared samples. The wettability of the samples was evaluated using contact angle measurements. As ZnO is hydrophilic in nature, the RT deposited samples showed a hydrophilic character, whereas the ZnO TFs deposited at 250 °C demonstrated a hydrophobic character. The XRD results showed a higher degree of crystallinity for samples deposited on heated substrates. Because of this higher crystallinity, the surface energy decreased, and the contact angle increased. Moreover, by using 2 mL solution, better surface coverage and roughness were obtained for the ZnO TFs. However, by exploiting the distance of the spray to the samples size distribution and surface coverage can be controlled, the samples deposited at 30 mL showed a uniform particle size distribution from 30–40 nm. In addition, the photoactivity of the samples was tested by the degradation of rhodamine B dye. Substrates prepared with a 2 mL solution sprayed at 20 cm showed higher dye degradation than other samples, which can play a vital role in self-cleaning. Hence, by changing the said parameters, the ZnO thin film properties on glass substrates were optimized for self-cleaning diversity.     

Advances in Trace Element Supplementation for Parenteral Nutrition

Parenteral nutrition (PN) provides support for patients lacking sufficient intestinal absorption of nutrients. Historically, the need for trace element (TE) supplementation was poorly appreciated, and multi-TE products were not initially subjected to rigorous oversight by the United States Food and Drug Administration (FDA). Subsequently, the American Society for Parenteral and Enteral Nutrition (ASPEN) issued dosage recommendations for PN, which are updated periodically. The FDA has implemented review and approval processes to ensure access to safer and more effective TE products. The development of a multi-TE product meeting ASPEN recommendations and FDA requirements is the result of a partnership between the FDA, industry, and clinicians with expertise in PN. This article examines the rationale for the development of TRALEMENT^® (Trace Elements Injection 4*) and the FDA’s rigorous requirements leading to its review and approval. This combination product contains copper, manganese, selenium, and zinc and is indicated for use in adults and pediatric patients weighing ≥10 kg. Comprehensive management of PN therapy requires consideration of many factors when prescribing, reviewing, preparing, and administering PN, as well as monitoring the nutritional status of patients receiving PN. Understanding patients’ TE requirements and incorporating them into PN is an important part of contemporary PN therapy.     

噻唑烷二酮类药物对糖尿病肾病的直接作用及其机制

近年的研究显示 ,噻唑烷二酮类药物 (TZD)具有不依赖于胰岛素增敏作用的肾直接保护作用 ,在未降低糖尿病大鼠高血糖水平的情况下 ,TZD可减少清蛋白尿 ,抑制肾小球系膜肥大及细胞外基质 (ECM)增生。其可能的作用机制是 :在高血糖状态下 ,TZD通过激活肾小球中二酰基甘油激酶 (DGK) ,抑制二酰基甘油 (DAG) 蛋白激酶C(PKC) 细胞信号调节激酶 (ERK)通路活性而改善肾小球高滤过状态、抑制ECM蛋白的过度产生。也有研究认为 ,TZD与改善硫酸乙酰肝素原多糖 (HSPG)合成及硫酸化、从而抑制肾小球基膜 (GBM)外疏松层的阴离子位点有关。此外 ,TZD可能通过调节肾小球系膜细胞的表型转化达到肾保护作用。     

复方益气化痰方及其拆方对抑郁模型大鼠血清锌、铜水平的影响

目的:探讨益气化痰方(人参、清半夏、陈皮、茯苓)及其拆方对慢性轻度不可预知应激(CUMS)模型大鼠血清锌、铜含量的影响.方法:健康雄性SD大鼠60只,随机分为5组.采用Katz刺激方法制备CUMS抑郁模型.在应激的第2天开始,按前期工作中得出了相应的效应中药及其各拆方最佳药物配比熬制中药浓缩剂,调节锌、铜方(3.25 g·kg-1组)和益气化痰方(7.0 g·kg-1)组按提取液10 mL· kg-灌胃,阳性药物组按10 mg·kg-1ig马普替林混悬液给药,模型组和正常对照组按10 mL·kg-1给予等量的生理盐水,持续给药至第23天.实验过程中,定期测定水平得分、竖直得分、修饰次数、大便颗粒数及糖水消耗量.于第23天处死大鼠,采集血样.采用原子吸收法测定各组大鼠血清锌、铜水平的含量.结果:采用孤养和CUMS刺激方法成功制备动物抑郁模型.模型组血清铜含量较正常组明显升高、血清锌含量较正常组明显降低;而益气化痰方组与模型组比较均能够逆转上述改变;其中调节锌铜方组可以显著提高血清锌的水平及降低血清铜水平.结论:益气化痰方具有良好的抗抑郁作用,同时能逆转大鼠行为学、体内微量元素锌和铜的改变;其中起主要作用的可能为调节锌铜方药.     

Iron,zinc and calcium dialyzability from extruded product based on whole grain amaranth (Amaranthus caudatus and Amaranthus cruentus) and amaranth/Zea mays blends

Amaranth is a Native American grain appreciated for its high nutritional properties including high mineral content. The aim of this study was to evaluate the availability of Fe, Zn and Ca from extruded products made with two varieties of amaranth and their mixtures with maize at two levels of replacement. Mineral availability was estimated using dialyzability method. The contents of Fe (64.0–84.0 mg/kg), Ca (1977.5–2348.8 mg/kg) and Zn (30.0–32.1 mg/kg) were higher in amaranth than in maize products (6.2, 19.1, 9.7 mg/kg, respectively). Mineral availability was in the range of (2.0–3.6%), (3.3–11.1%) and (1.6–11.4%) for Fe, Ca and Zn, respectively. Extruded amaranth and amaranth/maize products provide higher amount of Fe and Ca than extruded maize. Extruded amaranth products and amaranth addition to maize could be an interesting way to increase nutritional value of extruded products.     

Effect of alpha tocopheryl succinate on adenylate cyclase activity in murine neuroblastoma cells in culture.

Alpha tocopheryl succinate treatment (6-8 micrograms/ml), which inhibited the growth of murine neuroblastoma (NBP2) cells (46 +/? 3%), reduced basal and prostaglandin (PG)E1- and PGA2-stimulated adenylate cyclase (AC) activity in vitro. It also inhibited sodium fluoride (NaF)- and forskolin-stimulated AC activity, suggesting that the effect of vitamin E succinate on AC activity is mediated via stimulatory GTP-binding protein (Gs) and catalytic subunit. Vitamin E succinate-induced reduction of AC activity is not strictly related to inhibition of cell growth. This is substantiated by the finding that, although retinoic acid and butylated hydroxyanisole reduced the growth by over 50%, they did not inhibit AC activity. On the other hand, 4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone (R020-1724, 200 micrograms/ml), which inhibited growth (73 +/? 3%) and induced differentiation in NB cells, increased basal and PGE1-stimulated AC activity. Vitamin E succinate treatment also reduced PGE1- and PGA2-AC activity in murine fibroblasts (L-cells) without inhibiting growth.