The effects of calcium and magnesium on inhibitory junctional transmission in smooth muscle of guinea pig small intestine

Summary The membrane potential of smooth muscle cells in the circular layer of the guinea pig ileum was recorded using intracellular electrodes. Transmural stimulation, in the presence of atropine, caused a transient hyperpolarization, an inhibitory junction potential (IJP). IJP's are thought to result from the action of transmitter released from intramural inhibitory nerves. It has been reported that, in the guinea pig jejunum, the amplitude of the IJP resulting from field stimulation is not altered by changes in the calcium and magnesium ion concentration in the bathing solution. Experiments reported here have shown that the IJP amplitude decreased markedly on reducing the calcium ion concentration and or increasing the magnesium ion concentration. Indirect evidence is presented suggesting that the decrease in amplitude of the IJP is due to a decrease in the amount of transmitter released.     

Influence of caffeine,Ca2+, and Mg2+ on ryanodine depression of the tension transient in skinned myocardial fibers of the rabbit

Ryanodine, a blocker for Ca²⁺-release channels of the sarcoplasmic reticulum (SR Ca²⁺-release channels), induces depression of myocardial contraction in isolated intact muscle, which is consistent with depression of the caffeine-induced tension transient in skinned muscle fibers. In isolated SR, ryanodine binds to a specific receptor with high affinity, and this binding is enhanced by caffeine and increasing Ca²⁺ and decreased by increasing Mg²⁺. The aim of this study was to test the hypothesis that depression of myocardial contraction is mediated by changes in ryanodine-receptor binding properties. Accordingly, factors (caffeine, Ca²⁺, and Mg²⁺) affecting ryanodine-receptor binding properties in the isolated SR membrane were studied in skinned myocardial fibers from adult rabbits. The depression of the caffeine-induced tension transient by ryanodine (ryanodine depression) influenced by these three factors was measured. In a dose-dependent manner, increasing caffeine or Ca²⁺ concentrations enhanced the ryanodine depression. The concentrations for 50% ryanodine depression (IC₅₀) approximated 7mM for caffeine, and pCa 5.25 for Ca²⁺. When 1 M ryanodine and 25 mM caffeine were combined, ryanodine depression was independent of Ca²⁺ at low Ca²⁺ concentrations (20%–30% at pCa>8 and 7.5) and was a direct function of Ca²⁺ at higher concentrations (pCa 7.5–6.0 with IC₅₀ approx. pCa 6.75). In contrast, increasing Mg²⁺ reduced the ryanodine depression with IC₅₀ approximately equal to pMg 3.3. In conclusion, the caffeineor Ca²⁺-enhanced, and Mg²⁺-reduced ryanodine depression observed in this study is consistent with known ryanodinereceptor binding properties.     

血液灌流对硫线磷和硫酸阿托品的吸附作用

目的 定量研究血液灌流对有机磷农药硫线磷和其解毒药阿托品的吸附作用.方法 模拟临床血液灌流装置,对含硫线磷和硫酸阿托品的血样进行灌流吸附,分别用毛细管气相色谱法和高效液相色谱法测定硫线磷和硫酸阿托品的残留量.结果 吸附剂用量为0.5、1.0和1.5 g,包膜活性炭在灌流2.0 h后硫线磷的清除率均能达到90%以上,硫酸阿托品的清除率依次为61.9%、84.9%和88.9%;HA230树脂在灌流1.5 h后硫线磷清除率都达到90%以上,硫酸阿托品的清除率也依次高达88.0%、97.2%和98.4%;包膜活性炭灌流3.0h后,硫酸阿托品与硫线磷的比值最高为灌流前的10.1倍,而HA230树脂灌流后,此比值最高为灌流前的6.7倍.结论 包膜活性炭和HA230吸附树脂血液灌流1.5～2.0 h均能清除血中大部分硫线磷,而且均能增加血中硫酸阿托品和硫线磷浓度的比值.     

接触乙烯类或苯类对孕妇及新生儿姊妹染色单体交换和微核的影响

取因职业而接触乙烯类或苯类的孕妇静脉血和他们新生儿脐带血进行ＳＣＥ和ＭＮ测定。发现接触乙烯类或苯类的母血ＳＣＥ（８．５５±０．８４，９．４４±１．１２）均高于对照组（７．６８±１．４０），他们新生儿脐带血ＳＣＥ（８．９４±１．４３，８．７５±０．８８）也高于对照组（６．７１±１．２７）。接触乙烯类和苯类的母血微核率（０．８３３‰，０．７２７‰），高于对照组（０．２６７‰），他们新生儿脐血微核率（０．７５‰，０．８１８‰）也高于对照组（０．２６７‰）。我们还发现母亲孕期被动吸烟增强了这两类诱变剂对他们后代的遗传毒性。     

大鼠内毒素休克肝线粒体Ca^2＋,Mg^2＋含量变化与线粒体损伤

本文在大鼠内毒素休克模型上，观察了肝线粒体结构和功能与Ｃａ＾２＋，Ｍｇ＾２＋含量变化的关系。结果发现：休克动物肝组织和线粒体的Ｃａ＾２＋浓度升高，Ｍｇ＾２＋浓度下降与正常对照组相比有非常显著性差异；用图像分析仪定量分析显示线粒体结构明显受损，线粒体标志酶之一－琥珀酸脱氢酶（ＳＤＨ）活性明显下降，本文认为组织和线粒体内Ｍｇ＾２＋／Ｃａ＾２＋比值下降是休克细胞不可逆损伤重要因素之一。     

C57BL/6哮喘小鼠细胞内镁含量与肺组织β2受体mRNA表达的相关性研究

目的：探讨细胞内镁含量对C57BL/6哮喘小鼠肺组织β₂受体mRNA表达的影响。方法:健康4－6周龄清洁级雌性C57BL/6小鼠96只，体重(12±2)g，随机数字表法分为A、B、C、D 4组，每组各24只。应用鸡卵蛋白(OVA)建立哮喘小鼠模型。A、B组予低镁饲料喂食，C、D组予正常镁饲料喂食。B、D组腹腔内注射沙丁胺醇诱导β₂受体低调节，A、C组腹腔内注射生理盐水作对照。第1 d、21 d、34 d各组分别随机抽取8只检测血浆Mg2+、红细胞内Mg2+、肺组织β₂受体mRNA及蛋白表达。 结果:1 d血浆Mg2+、红细胞内Mg2+、肺组织β₂AR mRNA及蛋白表达各组间差异无显著（均P>0.05）。21 d、34 d C组血浆Mg2+、红细胞内Mg2+、肺组织β₂AR mRNA及蛋白表达均显著高于A组［21 d：(0.84±0.09)mmol/L vs （0.57±0.10)mmol/L、(2.39±0.14)mmol/L vs （2.11±0.08)mmol/L、(0.75±0.09)mmol/L vs （0.59±0.06)pmol/g、（88.50±8.50)pmol/g vs （60.10±7.70)pmol/g，均P<0.05；34 d：(0.67±0.10)mmol/L vs (0.51±0.09)mmol/L、(2.17±0.08)mmol/L vs (2.05±0.09)mmol/L、(0.61±0.05)pmol/g vs (0.53±0.06)pmol/g、(76.60±7.10)pmol/g vs (58.00±7.60)pmol/g，均P<0.05］；21 d、34 d D组血浆Mg2+、红细胞内Mg2+、肺组织β₂AR mRNA及蛋白表达亦显著高于B组［21 d：(0.95±0.33)mmol/L vs (0.46±0.09)mmol/L、(2.32±0.18)mmol/L vs (1.87±0.14)mmol/L、(0.73±0.10)pmol/g vs (0.43±0.07)pmol/g、(96.90±8.00)pmol/g vs (47.90±4.90)pmol/g，均P<0.05；34 d：(0.71±0.10)mmol/L vs (0.31±0.08)mmol/L、(1.66±0.13)mmol/L vs (1.45±0.16)mmol/L、(0.40±0.07)pmol/g vs (0.33±0.05)pmol/g、(61.50±3.20)pmol/g vs (35.30±7.10)pmol/g，均P<0.05］。结论:细胞内镁缺乏的C57BL/6哮喘小鼠肺组织β₂受体表达减少，在激动剂作用下更易发生β₂受体低调节。     

New computed radiography using scanning laser stimulated luminescence

Summary This short paper summarizes the basic concept and the technology of a new computed radiographic system which uses an energy-storage phosphorus panel called Imaging Plate as an image sensor. The Imaging Plate can be used to obtain radiographs in exactly the same way as the screen-film combination is used in conventional radiography. The system eliminates the drawbacks of conventional screen-film radiography by combining digital image processing and digitization of the x-ray energy pattern utilizing scanning laser stimulated luminescence.The major part of this paper was originally delivered at the 1984 AAPM Annual Summer School which was held on July 22–27 at University of Notre Dame, USA. Modified for the publication in the Neurosurgical Review.     

Micronutrients and Markers of Oxidative Stress and Inflammation Related to Cardiometabolic Health: Results from the EHES-LUX Study

Metabolic syndrome (MetS) characteristics include chronic inflammation and elevated oxidative stress. This study assessed associations between circulating concentrations of micronutrients/phytochemicals and inflammatory/oxidative stress markers with MetS and MetS components. Adults (N = 606) from the European Health Examination Survey in Luxembourg (2013–2015) were randomly selected. We performed a multivariable logistic regression model using the least absolute shrinkage and selection operator to identify MetS-associated variables. Participants with MetS had higher concentrations of C-reactive protein (CRP), 8-iso-prostaglandin F2α, leptin, insulin, and vitamins E/A, but lower concentrations of adiponectin, beta-carotene, and oxidized low-density lipoprotein. A one-unit increase in log-CRP was associated with 51% greater odds of MetS (OR = 1.51 (95% CI: 1.16, 1.98)). Adults with a one-unit increase in log-leptin were 3.1 times more likely to have MetS (3.10 (2.10, 4.72)). Women with a one-unit increase in vitamin A were associated with 3% increased odds of MetS (1.03 (1.01, 1.05)), while those with a one-unit increase in log-adiponectin were associated with 82% decreased odds (0.18 (0.07, 0.46)). Chronic inflammation best characterized adults with MetS, as CRP, adiponectin, and leptin were selected as the main MetS determinants. Micronutrients did not seem to affect MetS, except for vitamin A in women.     

Proanthocyanidins and Flavan-3-ols in the Prevention and Treatment of Periodontitis—Immunomodulatory Effects,Animal and Clinical Studies

This paper continues the systematic review on proanthocyanidins and flavan-3-ols in the prevention and treatment of periodontal disease and covers the immunomodulatory effects, and animal- and clinical studies, while the other part discussed the direct antibacterial properties. Inflammation as a major response of the periodontal tissues attacked by pathogenic microbes can significantly exacerbate the condition. However, the bidirectional activity of phytochemicals that simultaneously inhibit bacterial proliferation and proinflammatory signaling can provide a substantial alleviation of both cause and symptoms. The modulatory effects on various aspects of inflammatory and overall immune response are covered, including confirmed and postulated mechanisms of action, structure activity relationships and molecular targets. Further, the clinical relevance of flavan-3-ols and available outcomes from clinical studies is analyzed and discussed. Among the numerous natural sources of flavan-3-ols and proanthocyanidins the most promising are, similarly to antibacterial properties, constituents of various foods, such as fruits of Vaccinium species, tea leaves, grape seeds, and tannin-rich medicinal herbs. Despite a vast amount of in vitro and cell-based evidence of immunomodulatory there are still only a few animal and clinical studies. Most of the reports, regardless of the used model, indicated the efficiency of these phytochemicals from cranberries and other Vaccinium species and tea extracts (green or black). Other sources such as grape seeds and traditional medicinal plants, were seldom. In conclusion, the potential of flavan-3-ols and their derivatives in prevention and alleviation of periodontal disease is remarkable but clinical evidence is urgently needed for issuing credible dietary recommendation and complementary treatments.     

Polydatin Prevents Calcium Pyrophosphate Crystal-Induced Arthritis in Mice

Background: Polydatin is a stilbenoid with important antioxidant, anti-inflammatory, and immunomodulating properties. The aim of this study was to assess the anti-inflammatory preventive effect of polydatin in the mouse model of acute arthritis induced by calcium pyrophosphate (CPP) crystals. Methods: Acute arthritis was induced by the injection of a suspension of sterile CPP crystals into the ankle joint of Balb/c mice. Animals were randomized to receive polydatin or colchicine (the control drug) according to a prophylactic and a therapeutic protocol. The primary outcome was the variation of ankle swelling obtained after crystal injection and treatment, while histological parameters such as leukocyte infiltration, IL-1ß and CXCL1 levels and tissue expression were considered as secondary outcomes. Results: Prophylactic treatment with PD significantly diminished ankle swelling after 48 h from crystal injection. Secondary outcomes such as leukocyte infiltration, necrosis, edema, and synovitis were also decreased. PD caused a reduction in circulating levels of IL-1ß and CXCL1, as well as their tissue expression. By contrast, the therapeutic administration of PD did not have any beneficial effect. Conclusions: PD can effectively prevent acute inflammatory response to crystals in the mouse model of CPP crystal-induced arthritis. These results suggest that this bioactive compound might be used in the prevention of crystal-induced acute attacks in humans.