酒泉戈壁设施蔬菜重金属含量的测定及健康风险评估

目的 了解酒泉市戈壁设施种植的番茄、葫芦、黄瓜、辣椒、豆角中铅、砷、汞、镉的污染状况,评估人体摄入后的健康风险。方法 利用国家标准检验方法,在酒泉市总寨和东洞戈壁农业产业园区采集检测274份主栽蔬菜中铅、砷、汞、镉含量,结合单因子污染指数和内梅罗污染指数法对蔬菜受重金属污染的程度进行评价,利用靶标污染系数法对蔬菜中重金属对人体的健康风险进行评估。结果 274份蔬菜中铅、砷、汞和镉的含量范围分别为0～0.050 1 mg/kg、0～0.053 8 mg/kg、0～0.001 0 mg/kg和0～0.048 8 mg/kg,平均含量分别为0.010 3、0.010 3、0.000 2和0.008 7 mg/kg,均未超出国家标准规定的食品中污染物限量。5种蔬菜中4种重金属的污染指数均低于0.7,靶标危害系数均小于1。结论 酒泉市总寨和东洞戈壁农业产业园区主栽的5种蔬菜受铅、砷、汞、镉污染程度较轻,属于清洁水平,处于安全级别,膳食摄入风险较低。对比其它地区蔬菜,酒泉戈壁设施蔬菜中重金属含量总体不高,与有机设施蔬菜基地结果接近。     

Myricetin as a Promising Molecule for the Treatment of Post-Ischemic Brain Neurodegeneration

The available drug therapy for post-ischemic neurodegeneration of the brain is symptomatic. This review provides an evaluation of possible dietary therapy for post-ischemic neurodegeneration with myricetin. The purpose of this review was to provide a comprehensive overview of what scientists have done regarding the benefits of myricetin in post-ischemic neurodegeneration. The data in this article contribute to a better understanding of the potential benefits of myricetin in the treatment of post-ischemic brain neurodegeneration, and inform physicians, scientists and patients, as well as their caregivers, about treatment options. Due to the pleiotropic properties of myricetin, including anti-amyloid, anti-phosphorylation of tau protein, anti-inflammatory, anti-oxidant and autophagous, as well as increasing acetylcholine, myricetin is a promising candidate for treatment after ischemia brain neurodegeneration with full-blown dementia. In this way, it may gain interest as a potential substance for the prophylaxis of the development of post-ischemic brain neurodegeneration. It is a safe substance, commercially available, inexpensive and registered as a pro-health product in the US and Europe. Taken together, the evidence available in the review on the therapeutic potential of myricetin provides helpful insight into the potential clinical utility of myricetin in treating neurodegenerative disorders with full-blown dementia. Therefore, myricetin may be a promising complementary agent in the future against the development of post-ischemic brain neurodegeneration. Indeed, there is a scientific rationale for the use of myricetin in the prevention and treatment of brain neurodegeneration caused by ischemia.     

梧桐花粉主要变反原的分离纯化

以离子交换和凝胶过滤层析对梧桐花粉变应原进行分离和纯化,采用生物素-链霉亲和素酶联免疫吸附分析法（BSA-ELISA）测定其抗原活性,得到两个具高活性的单一变应原组分PT13和PT53。经SDS-聚丙烯酰胺凝胶电泳测得它们的分子质量分别为20ku和18ku。     

低氧环境对椎间盘自发性吸收的影响及其作用机制

目的探讨低氧环境对椎间盘自发性吸收的影响及其作用机制。方法取SPF级成年日本大耳兔9只,雌雄不限,平均体质量2 kg。将兔处死后取脊柱髓核组织,经消化、分离、培养后获得传代髓核细胞,将生长良好的髓核细胞制成细胞悬液。根据不同时效的低氧环境将细胞分为5组对照组(常氧浓度下培养6 h)、低氧6 h组(2%O2浓度下培养6 h)、低氧12 h组(2%O2浓度下培养12 h)、低氧24 h组(2%O2浓度下培养24 h)和低氧48 h组(2%O2浓度下培养48 h)。采用实时聚合酶链反应法检测缺氧诱导因子(HIF)-1α、3型酸敏感离子通道(ASIC3)及水通道蛋白3(AQP3)mRNA表达水平,采用流式细胞仪检测各组髓核细胞凋亡情况。采用SPSS 24.0软件对数据进行分析。结果与对照组比较,低氧各组细胞凋亡率均明显升高,差异均有统计学意义(均P<0.01);与低氧12、24和48 h组比较,低氧6 h组细胞凋亡率最高,差异均有统计学意义(均P<0.01)。与对照组比较,低氧各组细胞HIF-1α和ASIC3 mRNA表达水平均明显上升,AQP3 mRNA表达水平均明显下降,差异均有统计学意义(均P<0.01);与低氧12、24和48 h组比较,低氧6 h组HIF-1α和ASIC3 mRNA表达水平最高,差异均有统计学意义(均P<0.01)。结论短时间低氧环境可以促进髓核细胞凋亡,从而加速椎间盘突出组织自发性吸收进程,其机制可能与HIF-1α和ASIC3的表达增加及AQP3的表达下降有关。     

阿奇霉素-离子交换树脂复合物的制备及其掩味与调控释药作用

为掩盖阿奇霉素(azithromycin,AZI)苦味和个性化调控药物释放速度以减少胃肠道刺激,分别以羟丙基纤维素(hydroxypropyl cellulose,HPC)和尤特奇RS100修饰制备速释型AZI-Amberlite^TM IRP64/HPC和缓释型AZI-Amberlite^TM IRP69/RS100进而组合以实现控制释放。对AZI-离子交换树脂复合物的载药量、药物利用率进行测定,通过差示扫描量热分析和X射线衍射对AZI-离子交换树脂复合物进行结构表征,测定其润湿度、掩味效果、体外溶出和释放行为。结果显示,形成的AZI-离子交换树脂复合物改变了药物原有的结晶状态,2.5%HPC修饰的AZI-Amberlite^TM IRP64/HPC和0.5%RS100修饰的AZI-Amberlite^TM IRP69/RS100掩味效果良好,两者以对应AZI含量为13∶67的比例组合可以实现AZI在前10 min的快速释放和后期的6 h内平稳释药。结果表明,经表面修饰制得的AZI-离子交换树脂复合物及其...     

Electrical Analysis of Fresh,Excised Human Skin: A Comparison with Frozen Skin

Samples of human allograft skin prepared without freezing ("fresh skin) were found to have electrical and sodium ion transport properties which differed only slightly from those of skin which had been similarly treated but stored frozen (frozen skin). The fresh skin samples were less permeable to sodium ions during passive diffusion and less conductive than frozen skin at low current levels. They were more permselective for sodium versus chloride during constant-current iontophoresis and showed slightly more asymmetry in their current–voltage properties. Overall, the electrical behavior of the two tissues was similar enough to support the use of frozen tissue in iontophoresis studies. However, caution should be exercised when considering the use of frozen skin for applications, such as those based on electroosmosis, where the observed differences could have a major impact on the results.     

离子交换树脂法与活性炭吸附法提取左旋多巴结果比较

以水和盐酸为溶剂从猫豆中提取左旋多巴,并对提取液分别用离子交换树脂法和活性炭吸附法富集左旋多巴,再分别用氨水和醇洗脱,经浓缩、精制得左旋多巴。实验结果表明,前法提取周期较长,平均提取率为2．50％,后法提取周期较短,平均提取率为2．66％,提示后法优于前法。     

猪血小板衍化生长因子的提取和纯化

目的 建立一种简单、经济的血小板衍化生长因子（PDGF）的纯化方法。方法 血小板衍化生长因子（PDGF）具有耐酸性（pH2.5）,耐热（100℃）以及耐受2%SDS的特性。采用酸醇提取、热处理、离子交换层析、分子筛等蛋白分离和纯化技术从猪血小板中提取和纯化PDGF。结果 猪血小板衍化生长因子（pPDGF）纯化倍数达7582倍,活性回收率为3%。结论 本方法简单、经济,纯化的猪血小板衍化生长因子(pPDGF）具有明显的生物学活性。     

Sources of Ca2+ in relation to generation of acetylcholine-induced endothelium-dependent hyperpolarization in rat mesenteric artery

1. The aim of the present study was to identify the sources of Ca²⁺ contributing to acetylcholine (ACh)-induced release of endothelium-derived hyperpolarizing factor (EDHF) from endothelial cells of rat mesenteric artery and to assess the pathway involved. The changes in membrane potentials of smooth muscles by ACh measured with the microelectrode technique were evaluated as a marker for EDHF release.
2. ACh elicited membrane hyperpolarization of smooth muscle cells in an endothelium-dependent manner. The hyperpolarizing response was not affected by treatment with 10 μM indomethacin, 300 μM N^G-nitro-L-arginine or 10 μM oxyhaemoglobin, thereby indicating that the hyperpolarization is not mediated by prostanoids or nitric oxide but is presumably by EDHF.
3. In the presence of extracellular Ca²⁺, 1 μM ACh generated a hyperpolarization composed of the transient and sustained components. By contrast, in Ca²⁺-free medium, ACh produced only transient hyperpolarization.
4. Pretreatment with 100 nM thapsigargin and 3 μM cyclopiazonic acid, endoplasmic reticulum Ca²⁺-ATPase inhibitors, completely abolished ACh-induced hyperpolarization. Pretreatment with 20 mM caffeine also markedly attenuated ACh-induced hyperpolarization. However, the overall pattern and peak amplitude of hyperpolarization were unaffected by pretreatment with 1 μM ryanodine.
5. In the presence of 5 mM Ni²⁺ or 3 mM Mn²⁺, the hyperpolarizing response to ACh was transient, and the sustained component of hyperpolarization was not observed. On the other hand, 1 μM nifedipine had no effect on ACh-induced hyperpolarization.
6. ACh-induced hyperpolarization was nearly completely eliminated by 500 nM U-73122 or 200 μM 2-nitro-4-carboxyphenyl-N,N-diphenylcarbamate, inhibitors of phospholipase C, but was unchanged by 500 nM U-73343, an inactive form of U-73122. Pretreatment with 20 nM staurosporine, an inhibitor of protein kinase C, did not modify ACh-induced hyperpolarization.
7. These results indicate that the ACh-induced release of EDHF from endothelial cells of rat mesenteric artery is possibly initiated by Ca²⁺ release from inositol 1,4,5-trisphosphate (IP₃)-sensitive Ca²⁺ pool as a consequence of stimulation of phospholipid hydrolysis due to phospholipase C activation, and maintained by Ca²⁺ influx via a Ni²⁺- and Mn²⁺-sensitive pathway distinct from L-type Ca²⁺ channels. The Ca²⁺-influx mechanism seems to be activated following IP₃-induced depletion of the pool.