Determination of nitrite in soil extracts and water samples by a nitrogen oxide electrode

Abstract

Work to evaluate the Orion nitrogen oxide electrode indicated that this electrode can be used satisfactorily for determination of nitrite in soil extracts and water samples. The electrode method of analysis described is simple, rapid, and precise, and its results agree closely with those obtained by the colorimetric method of Griess‐Ilosvay. The electrode method has the advantage that its results are not affected by color or turbidity or by Cu²⁺ and Hg²⁺ present in samples under analysis     

Above and Below Ground Measurements of Greenhouse Gases from Swine Effluent Amended Soil

Abstract

As a means of economic disposal and to reduce need for chemical fertilizer, waste generated from swine production is often applied to agricultural land. However, there remain many environmental concerns about this practice. Two such concerns, contribution to the greenhouse effect and stratospheric ozone depletion by gases emitted from waste‐amended soils, have not been thoroughly investigated. An intact core study at Auburn University (32 36′N, 85 36′W) was conducted to determine the source‐sink relationship of three greenhouse gases in three Alabama soils (Black Belt, Coastal Plain, and Appalachian Plateau regions) amended with swine waste effluent. Soil cores were arranged in a completely random design, and treatments used for each soil type consisted of a control, a swine effluent amendment (112 kg N ha^?1), and an ammonium nitrate (NH₄NO₃) fertilizer amendment (112 kg N ha^?1). During a 2‐year period, a closed‐chamber technique was used to determine rates of emission of nitrous oxide (N₂O)–nitrogen (N), carbon dioxide (CO₂)–carbon (C), and methane (CH₄)–C from the soil surface. Gas probes inserted into the soil cores were used to determine concentrations of N₂O‐N and CO₂‐C from depths of 5, 15, and 25 cm. Soil water was collected from each depth using microlysimeters at the time of gas collection to determine soil‐solution N status. Application of swine effluent had an immediate effect on emissions of N₂O‐N, CO₂‐C, and CH₄‐C from all soil textures. However, greatest cumulative emissions and highest peak rates of emission of all three trace gases, directly following effluent applications, were most commonly observed from sandier textured Coastal Plain and Appalachian Plateau soils, as compared to heavier textured Black Belt soil. When considering greenhouse gas emission potential, soil type should be a determining factor for selection of swine effluent waste disposal sites in Alabama.     

中药复方总多糖及其含药血清对小白鼠免疫功能的影响

分别给小鼠灌服复方总多糖、复方水煎剂、黄芪多糖、生理盐水后制备含药血清,用MTT法测定小鼠淋巴细胞增殖程度,用酶法一氧化氮试剂盒测定腹腔巨噬细胞一氧化氮的生成量,同时与各种药物的体外实验相比较.结果显示,复方总多糖及其含药血清均能促进小鼠脾脏淋巴细胞增殖和腹腔巨噬细胞一氧化氮的生成量,且效果优于复方水煎剂和黄芪多糖.     

硫横苯丁锡混合悬浮剂中苯丁锡含量的测定

本文介绍样品用二氯甲烷提取后，经薄层分离去除干扰，用硫酸 硝酸 过氧化氢消化，使苯丁锡转化成四价锡，以邻苯二酚紫-N-溴代十六烷基吡啶作显色剂，在波长660nm处进行比色测定，其标准偏差为0.04445，变异系数为0.87%，重现性好，方法平均回收率为99.61%。     

Serum nitrate and nitrite in dogs with spontaneous cardiac disease

The purpose of this study was to determine whether nitric oxide (NO) concentrations are high in dogs with chronic valvular disease (CVD) and dilated cardiomyopathy (DCM) compared to healthy controls and to determine whether NO concentrations are correlated with type of cardiac disease, disease severity, medical therapy, or serum tumor necrosis factor (TNF) and interleukin-1 (IL-1). Blood was collected from 32 dogs with DCM, from 10 dogs with CVD, and from 10 healthy controls. Indirect determination of NO concentrations was performed by a commercial photoabsorbance assay that uses a Greiss reagent to measure the concentration of nitrite and nitrate (NN), end products of NO metabolism. TNF and IL-1 activities were measured by bioassay. Mean NN concentrations were significantly higher in dogs with heart disease (median, 4.57 microM; range, 0.00-31.05 microM) than in controls (median, 0.00 microM; range, 0.00-6.16 microM; P = .04). NN concentrations in dogs with cardiac disease were not correlated with type or severity of cardiac disease, medication type, or TNF and IL-1 concentrations. NN concentrations were inversely correlated with fractional shortening. The results of this study suggest that metabolites of NO are increased in some dogs with cardiac disease, but these increases appear to be independent of disease severity, TNF and IL-1 concentrations, and type of pharmacologic intervention.     

二乙基己烯雌酚对成年仓鼠睾丸一氧化氮生成和生精细胞凋亡的影响

探讨了在二乙基己烯雌酚（DES）诱发成年动物生精细胞凋亡过程中睾丸一氧化氮（NO）生成和生精细胞一氧化氮合酶（eNOS和iNOs）表达的变化，以期为阐明DES诱发生精细胞凋亡机理的研究提供基础资料。成年雄性仓鼠皮下注射不同剂量DES（分别为0．01、0．1和1mg／kg体重），连续注射7d后取其睾丸，进行NO含量的测定和eNOS、iNOS免疫组化染色。电镜观察生精细胞超微结构的变化，并用TUNEL法检测睾丸中生精细胞凋亡的变化，苏丹Ⅲ染色法检测睾丸生精小管内脂滴分布的变化。结果显示：NO的生成与DES呈剂量依赖性。DES处理后，在1mg／kg体重剂量组，大量生精细胞表达eNOS和iNOS，并出现大量凋亡，退化的生精细胞胞浆内有大量髓样结构，并有大量脂滴分布于生精细胞内和细胞间。eNOS和iNOS阳性生精细胞与凋亡的生精细胞数量和类型基本一致，主要为精母细胞和圆形精子细胞。     

Preliminary experiments on mechanical stretch-induced activation of skeletal muscle satellite cells in vivo

We have shown in vitro that mechanical stretch triggers activation of quiescent satellite cells of skeletal muscle to enter the cell cycle through an intracellular cascade of events including nitric oxide (NO) synthesis that results in the release of hepatocyte growth factor (HGF) from its extracellular association and its subsequent presentation to signaling receptors. In order to explore the activation mechanism in vivo, stretch experiments were conducted in the living animal using our suspension model developed. This system used the weight of the hind portion of rats to stretch the inside muscles of the left hind limb suspended for a period of 0.5–2.0 h. At the end of the stretch period, the rats received an intraperitoneal injection of bromodeoxyuridine followed by immunocytochemistry for its incorporation as an index of satellite cell activation in vivo. Depending on the period of stretch, bromodeoxyuridine labeling was increased significantly over the contralateral unstretched leg or control muscle from untreated rats. A stretched muscle extract prepared from the 2 h stretched tissue by incubating it in PBS, showed the active form of HGF as revealed by immunoblotting and it could stimulate the activation of unstretched satellite cells. Also, administering NO synthase inhibitor L‐NAME prior to muscle stretch abolished the stretch activation of satellite cells. Therefore, the results from these experiments demonstrate that stretching muscle triggers NO synthesis and HGF release, which could activate satellite cells in vivo.     

Influence of transection of the cervical sympathetic trunk on content of NO and expression of NOS in placenta of rats with pregnancy-induced hypertension syndrome

AIM:To observe the influence of transection of the cervical sympathetic track (TCST) on the content of NO and the expression of eNOS mRNA and iNOS mRNA in placenta of the rats with pregnancy-induced hypertension syndrome (PIH).METHODS: Pregnant Wistar rats were randomly divided into 5 groups: control group (C): saline was injected subcutaneously from 14th day to 20th day of gestation;PIH group 1 (H1) and group 2 (H2): L-NAME was respectively injected with 125 mg/kg and 62.5 mg/kg,respectively,then the other procedures were the same as group C;Operation group (O): TCST was operated on 14th day of the gestation,then the other procedures were the same as group H1;sham operation group (S): the cervical sympathetic trunk was only separated and exposed on 14th day of the gestation,then the other procedures were the same as group H1.RESULTS: (1) Except the base value of the BP and protein in urine of the pregnant rats,all the parameters observed in group H1 and H2 were higher than those in group C significantly (P<0.01),and in group H2 were lower than those in group B1 markedly (P<0.01).(2) In comparison with those in group C,the size and body weigh of fetus in group H1,H2 decreased markedly (P<0.01).The above indexes in group H1 were lower than those in group H2 markedly (P<0.01,P<0.05).The changes of the rate of embryo absorption and fetal death,and deformity rate of the fetal rats were contrary to the above indexes.(3) The content of NO and the expression of eNOS mRNA and iNOS mRNA in placenta in group H1 and H2 were lower than those in group C markedly (P<0.01).Those in group H1 were lower than those in group H2 obviously (P<0.01,P<0.05).Those in group O were higher than those in group H1 markedly (P<0.01).CONCLUSION: TCST protects pregnant rats against PIH,and it was related to the mRNA expression of eNOS and iNOS and the content of NO in placenta tissue.