Cardiac copper,magnesium, and zinc in recent and old myocardial infarction

X-ray fluorescence spectrometry and atomic absorption spectrometry were used in a quantitative study of zinc, copper, and magnesium in 71 postmortal human hearts. Samples were obtained from individuals who had demonstrated no previous clinical or subsequent pathological findings of myocardial infarction and from victims of a recent or an old infarction. A significant difference (p<0.001) in the elemental levels was observed between the noninfarct and the recent infarct groups. The noninfarct group had higher cardiac levels of all three elements. However, the difference in elemental concentrations between the noninfarct and the old-infarct groups was not significant. Cardiac levels of zinc (p<0.001) and copper (p<0.01) were significantly greater in the old-infarct group than in the recent-infarct group. Magnesium levels were higher in the recent-and-old-infarct group than in the recent infarct group (p<0.01). It is possible that the elements are redistributed during myocardial infarction, and that uptake of these elements (from the serum pool) by the heart may be important in maintaining myocardial integrity and function.     

LCA of cleaning and degreasing agents in the metal industry

An LCA of cleaning and degreasing agents in the metal industry was carried out. A comparison was made between a solvent product (VOC: a mixture of dearomatised hydrocarbons) and two products derived from vegetable oils (VOFA: rapeseed methyl ester and ethylhexyl laurate derived from coconut oil). The comparison was based on 1000 kg of used product. Results from the inventory and characterisation show that VOFA are environmentally favourable on aspects related to their low volatility and their use of renewable resources. However, they are less favourable on aspects predominantly related to cultivation of the crops. The environmental favourability of VOFA compared to VOC is strongly dependent upon the amounts needed for the task to be performed. Incorporation of data from practical experience concerning the use and waste treatment of VOFA in the metal industry may possibly further improve the environmental profile of VOFA. This work was presented at the 17th Annual Meeting of the Society of Environmental Toxicology and Chemistry (SETAC), November 19,1996, in Washington, DC. It was one of a series of presentations during the LCA session.     

跑台运动改善海马线粒体功能提高APP/PS1小鼠学习记忆能力

为研究跑台运动对APP/PS1小鼠海马线粒体融合、分裂作用的影响,将遗传背景为C57BL/6的3月龄APP/PS1小鼠和野生小鼠各42只分别随机分为APP/PS1安静对照组（ADC,n=21）和运动组（ADE,n=21）,野生安静对照组（WTC,n=21）和运动组（WTE,n=21）。ADE、WTE组进行12周跑台运动,同时ADC、WTC组置于安静跑台环境。水迷宫实验检测小鼠的空间学习记忆能力,RT-PCR法检测线粒体功能关键酶的mRNA水平,Western印迹检测海马融合、分裂及线粒体关键酶的蛋白质表达情况,透射电镜观察海马线粒体融合、分裂状态。结果发现,6月龄APP/PS1小鼠学习记忆能力降低（P<0.05）;海马线粒体融合蛋白质Mfn1、Mfn2、Opa1表达降低（P<0.05）,线粒体分裂蛋白质Drp1、Mff表达增高（P<0.05）;线粒体膜结构模糊,嵴不明显,线粒体碎片增多,空泡化线粒体增多;线粒体呼吸关键酶COX IV及ATP合酶表达均下调（P<0.05）。12周跑台运动可逆转APP/PS1小鼠的上述变化,改善海马线粒体结构和功能,提高学习记忆能力。综上提示：12周跑台运动改善APP/PS1小鼠学习记忆能力的机制可能与其对线粒体结构与功能的改善有关。     

Rat liver metabollothionein interactions of silver,zinc, and cadmium

Weanling rats were fed diets either alone or with combinations of silver, elevated zinc, or elevated cadmium for 7 weeks. The rats were then killed, and the silver, zinc, and cadmium proteins isolated from the livers by gel filtration and ion exchange chromatography. When silver was fed alone in diet, low levels of this metal were eluted as two peaks from the ion exchange column. In contrast, when silver was fed with cadmium or elevated zinc, three metal-containing peaks were eluted from this ion exchange column. Amino acid analysis revealed that the major proteins binding these metals are metallothioneins, as judged by high cysteine content.     

青弋江鱼类分类群和功能群的α和β多样性纵向梯度格局

确定溪流鱼类多样性的时空分布格局可为鱼类多样性保护与管理提供科学基础。尽管溪流鱼类分类群多样性的纵向梯度格局已有大量报道, 但以鱼类生物学特征为基础的功能多样性研究较少。本文基于2009-2010年4个季度对青弋江1-5级溪流共15个样点的调查数据, 利用形态特征数据和食性构建了鱼类复合功能群, 研究了不同级别溪流间鱼类分类群和功能群组成及多样性的异同, 着重探讨了鱼类分类群和功能群的α和β多样性沿溪流纵向梯度的变化规律。采集到的56种鱼类可分为4个营养功能群和5个运动功能群, 共计14个“营养-运动”复合功能群。双因素交互相似性分析结果显示, 鱼类分类群和功能群组成都随河流级别显著变化, 但季节动态不显著; 双因素方差分析后发现, 鱼类分类群和功能群α、β多样性都随河流级别显著变化, 但受季节影响不显著。经回归分析, 分类群和功能群α多样性与河流级别大小呈显著的线性正相关, 但最大分类群α多样性出现于4级河流, 最大功能群α多样性在4级和5级河流间一致; 分类群和功能群β多样性与河流级别大小呈显著的二项式关系, 呈U型分布。分类群β多样性的空间变化主要取决于物种周转, 而功能群β多样性主要由嵌套所驱动。本研究表明, 沿着“上游-下游”的纵向梯度, 河流鱼类的α和β多样性的空间变化规律不同, 分类群和功能群α多样性的空间格局基本一致, 但分类群(主要是物种周转)和功能群β多样性(主要是功能嵌套)的空间变化过程的驱动机制不同。     

Cadmium,cobalt, chromium,and experimental myocardial infarction

In the case of experimental heart muscle infarction, the infarcted tissue of 18 pigs had a cadmium content of 0.38 μg/g dry weight and a cobalt content of 0.45 μg/g dry weight. In 25 non-infarcted pig hearts, the cadmium concentration amounted to 0.27 μg/g dry weight and the cobalt concentration to 0.37 μg/g dry weight. Thus, as far as the infarcted heart muscle tissue is concerned, there is a highly significant increase in the cadmium content (p<0.01) and a significant increase in cobalt content (p<0.05) compared to a non-infarcted heart. No differences were established with regard to chromium concentrations.     

New methods for estimating the numbers of synonymous and nonsynonymous substitutions

New methods for estimating the numbers of synonymous and nonsynonymous substitutions per site were developed. The methods are unweighted pathway methods based on Kimura's two-parameter model. Computer simulations were conducted to evaluate the accuracies of the new methods, Nei and Gojobori's (NG) method, Miyata and Yasunaga's (MY) method, Li, Wu, and Luo's (LWL) method, and Pamilo, Bianchi, and Li's (PBL) method. The following results were obtained: (1) The NG, MY, and LWL methods give overestimates of the number of synonymous substitutions and underestimates of the number of nonsynonymous substitutions. The major cause for the biased estimation is that these three methods underestimate the number of synonymous sites and overestimate the number of nonsynonymous sites. (2) The PBL method gives better estimates of the numbers of synonymous and nonsynonymous substitutions than those obtained by the NG, MY, and LWL methods. (3) The new methods also give better estimates of the numbers of synonymous and nonsynonymous substitutions than those obtained by the NG, MY, and LWL methods. In addition, estimates of the numbers of synonymous and nonsynonymous sites obtained by the new methods are reasonably accurate. (4) In some cases, the new methods and the PBL method give biased estimates of substitution numbers. However, from the number of nucleotide substitutions at the third position of codons, we can examine whether estimates obtained by the new methods are good or not, whereas we cannot make an examination of estimates obtained by the PBL method. (5) When there are strong transition/transversion and nucleotide-frequency biases like mitochondrial genes, all of the above methods give biased estimates of substitution numbers. In such cases, Kondo et al.'s method is recommended to be used for estimating the number of synonymous substitutions, although their method cannot estimate the number of nonsynonymous substitutions and is time-consuming. These results, particularly result (1), call for reexaminations of some genes. This is because evolutionary pictures of genes have often been discussed on the basis of results obtained by the NG, MY, and LWL methods, which are favorable for the neutral theory of molecular evolution.     

Magnesium,calcium, copper,and zinc in meals

Meals of 12 diets were prepared from conventional foods with precautions against contamination by metallic elements because of epidemiologic associations between ischemic heart disease and the metabolism of magnesium, calcium, copper, and zinc. Magnesium, calcium, copper, and zinc were measured by atomic absorption spectrometry with satisfactory accuracy and precision. The mean daily amount of copper in the diets was less than the apparent adult requirement. Mean amounts of magnesium and zinc were close to apparent requirements; however, adults consuming amounts less than one standard deviation below these means may be depleting body stores and be at risk of pathology. Magnesium and copper were highly correlated (r=0.849,P=0.0001) in meals. This and other significant correlations probably will prevent the relationships of these elements to ischemic heart disease from being elucidated by epidemiology. Metabolic experiments will be necessary to differentiate among several hypotheses.     

Surface thermodynamics of normal and pathological human granulocytes

Surface tensions of normal and pathological granulocytes were determined by (1) adhesion to solid substrates of different surface tensions while suspended in liquid media of different surface tensions, and by (2) measurement of cell-liquid-vapor contact angles obtained with sessile drops of saline water on cell monolayers. The results obtained by the two different methods were in close conformation with one another. With the cell adhesion emthod some residual leukocyte adhesion still persists even under conditions where there no longer is a van der Waals attraction between cells and solid substrate. At low ionic strength and by the abolishment of all multivalent cations through the admixture of EDTA, that residual cell adhesion virtually disappears (with normal as well as with pathological granulocytes), indicating that the earlier residual cell adhesion did indeed arise from electrostatic interactions mediated by multivalent cations (probably Ca²⁺). Comparison of the capacities for engulfment and the surface thermodynamics data of normal and pathological granulocytes obtained in this study leads to the novel observation that the phagocytic episode from half to complete engulfment of bacterial particles by granulocytes appears to be the crucial step from the thermodynamic point of view.     

Cadmium,copper, and zinc levels in the rice and rice field soil of Houston,Texas

Fifty-one pairs of hulled rice samples and the soil from which each rice sample was grown were analyzed for heavy metals in August, 1979, in order to estimate the background contamination of cadmium (Cd), copper (Cu), and zinc (Zn) in rice grown in the Houston, Texas area. Both samples were divided into three groups by soil types and colors. The cadmium concentration in Texas rice was only one-half to one-quarter lower than that of Asian rice. However, the levels of Cu and Zn in rice in Texas were similar to those reported. Soil heavy metals were lower than ever reported, but these values were consistent with the geochemical characteristics of the Texas Houston area. No particular relationship was found between the three metals in rice and the metals in soil where the sampled rice was grown.     

Uptake of selenate and selenite by isolated intestinal brush border membrane vesicles from pig,sheep, and rat

Selenate and selenite uptakes by isolated intestinal brush border membrane vesicles (BBMV) from pig, sheep, and rat were investigated. Selenate uptake into jejunal and ileal, but not duodenal, BBMV from pig was stimulated by an inwardly directed transmembrane Na⁺ gradient (Na _out ⁺ >Na _in ⁺ ). Selenate transport into rat ileal and sheep jejunal BBMV was also enhanced in the presence of a Na⁺ gradient. Unlike selenate uptake, selenite uptake was not Na⁺ dependent, neither in pig small intestine nor in sheep jejunum and rat ileum. Uptake of selenate represented real uptake into the vesicular lumen, whereas selenite uptake was a result of an extensive binding of⁷⁵Se to the membranes. Thiosulfate at a 250-fold concentration of selenate completely inhibited Na⁺-dependent selenate uptake into pig jejunal BBMV. Furthermore, Na⁺-dependent sulfate uptake was totally inhibited in the presence of a 250-fold selenate concentration. The results clearly show that selenate transport across the BBM of pig jejunum and ileum, sheep jejunum, and rat ileum is partially energized by a transmembrane Na⁺ gradient. Moreover, it is concluded from the results that there exists a common transport mechanism for sulfate and selenate in the BBM. The extensive binding of⁷⁵Se from⁷⁵Se-labeled selenite to the membranes could be from a spontaneous reaction of selenite with membrane-associated SH groups.     

Investigation of riboflavin sensitized degradation of purine and pyrimidine derivatives of DNA and RNA under UVA and UVB

DNA and RNA undergo photodegradation in UVC (200-290 nm) due to direct absorption by the purine and pyrimidine bases. Limited effects are observed under UVB (290-320 nm) or UVA (320-400 nm). We have observed that an endogenous photosensitizer, riboflavin (RF), upon exposure to UVB or UVA can extensively damage the DNA and RNA bases. Guanine, uracil, thymine, adenine and cytosine were degraded by 100%, 82%, 60.4%, 46.3% and 10.3% under UVA (12 J) and by 100%, 54.1%, 38.9%, 42.2% and <1.0% under UVB (6 J), respectively. Guanosine and deoxyguanosine were degraded by 98 ± 1.0% and 80 ± 1.0% under UVA (4 J) and UVB (12 J), respectively. With an exception of GMP (53-82%), dGMP (51-88%) and to some extent TMP (3-4%) the remaining nucleosides and nucleotides were resistant to RF-induced photodecomposition. The photodegradation of G derivatives by RF was 2-fold higher than a well known photodynamic agent rose bengal. A comparison of the intensities of UVA and UVB sources used in this study with natural sunlight suggests that exposure with the latter along with an endogenous photosensitizer can have similar effects on DNA and RNA depending upon the duration of exposure.     

深挖垦复对锥栗重要农艺性状及土壤理化性质的影响

为探索锥栗林地高效的土壤管理方式,提升我国锥栗栽培管理技术水平,进而提高其产量、品质以及经济效益。该研究采用全垦和环垦两种方式对锥栗林地进行连续4年的深挖垦复,通过测定垦复前后土壤理化性质变化以及锥栗树体生长、叶片表型和生理特征、结果性状、产量及品质等重要农艺性状,统计数据并进行对比分析。结果表明:(1)深挖垦复对锥栗林地土壤理化性质改善效果显著,两种垦复方式土壤容重较垦复前降低31.21%及以上(0～30 cm处),土壤含水率、土壤孔隙度、有机质含量以及各种大量元素含量较垦复前和对照均有不同程度的增加,土壤肥力及其保水保肥能力显著增强。(2)环垦区土壤有机质含量、有效磷含量以及交换性镁含量高于全垦区,其土壤有机质含量较垦复前增加40.59%,远高于全垦增加幅度(17.76%),从土壤保肥能力的角度来看,环垦效果优于全垦。(3)土壤肥力的提升增强了其对锥栗叶片的供肥能力,使得叶片含水率、叶绿素含量以及各种矿质元素含量显著增加,从而提升其光合作用能力。(4)深挖垦复对锥栗树体生长、结实能力、产量及品质同样具有显著的提升效果,其中全垦和环垦区单位面积产量分别是对照的1.75倍和1.33倍,且栗苞总重、单果质量、出籽率、可溶性糖含量以及磷、钾元素含量显著高于对照,而空苞率显著低于对照。综上,深挖垦复是改良林地土壤和提高锥栗生产力的有效举措。     

Immunological properties of low molecular-weight proteins binding heavy metals in rat kidney and liver

Two homogenous fractions of hepatic metallothioneins ((Cd,Zn) MT-1 and (Cd,Zn) MT-2) and renal metal binding proteins ((Bi,Cu) BP-1 and (Bi,Cu) BP-2) were isolated from rats exposed to heavy metals and specific antisera to them were produced in rabbits.These antisera were tested by immunodiffusion and immunoelectrophoresis for their ability to bind different fractions of hepatic Cd,Zn -metallothionein and renal (Bi,Cu)-, (Hg,Cu)- and (Cd,Cu)-binding proteins. It was found that anti (Bi,Cu) BP antisera did not cross-react with hepatic (Cd,Zn) MT-1 and (Cd,Zn) MT-2. Strong immunological cross-reactions were detected between anti (Bi,Cu) BP antisera and individual forms of (Cd,Cu)-, (Hg,Cu)- and (Bi,Cu)-binding proteins isolated from rat kidneys.     

Seeds and seedlings of oaks suffer from mammals and molluscs close to phylogenetically isolated,old adults

Background and AimsMammals and molluscs (MaM) are abundant herbivores of tree seeds and seedlings, but how the trees and their environment affect MaM herbivory has been little studied. MaM tend to move much larger distances during the feeding stage than the more frequently studied insect herbivores. We hypothesize that MaM (1) select and stay within the patches that promise to be relatively the richest in seeds and seedlings, i.e. patches around adult trees that are old and within a distantly related, less productive neighborhood; and (2) try to remain sheltered from predators while foraging, i.e. mammals remain close to adult trees or to cover by herbs while foraging, and might force their mollusc prey to show the opposite distribution.MethodsWe exposed oak acorns and seedlings in a temperate forest along transects from adult conspecifics in different neighbourhoods. We followed acorn removal and leaf herbivory. We used exclusion experiments to separate acorn removal by ungulates vs. rodents and leaf herbivory by insects vs. molluscs. We measured the size of the closest conspecific adult tree, its phylogenetic isolation from the neighbourhood and the herbaceous ground cover.Key ResultsConsistent with our hypothesis, rodents removed seeds around adult trees surrounded by phylogenetically distant trees and by a dense herb cover. Molluscs grazed seedlings surrounding large conspecific adults and where herb cover is scarce. Contrary to our hypothesis, the impact of MaM did not change from 1 to 5 m distance from adult trees.ConclusionsWe suggest that foraging decisions of MaM repulse seedlings from old adults, and mediate the negative effects of herbaceous vegetation on tree recruitment. Also, an increase in mammalian seed predation might prevent trees from establishing in the niches of phylogenetically distantly related species, contrary to what is known from insect enemies.     

Studies on the relations of selenium and Keshan disease

Keshan disease is an endemic cardiomyopathy of unknown cause in The People’s Republic of China that occurs most frequently in children under 15 years of age and women of child-bearing age. Studies of children 1–9 years old in Mianing County of Sichuan Province have indicated that Keshan disease is a selenium responsive condition. Incidence rates of 9.5–13.5/1000 in 1974–1975 were reduced to 1–2/1000 in children treated with a tablet weekly of 0.5–1 mg sodium selenite. During 1974–1977, only 21 cases of the disease occurred in 36,603 treated children, compared with 106 cases in 9430 untreated children, of whom 53 died and 5 still have insufficient heart function. Occurrence of the disease was invariably associated with a lower selenium content of cereals, and of hair (less than 0.12 ppm Se) in residents from affected, compared with non-affected, areas. The dose relationship between selenium and regional characteristics of Keshan disease suggests that it is probably a biogeochemical disease; other etiological factors have also been considered.     

Deuterium exchange and mass spectrometry reveal the interaction differences of two synthetic modulators of RXRalpha LBD

Protein amide hydrogen/deuterium (H/D) exchange was used to compare the interactions of two antagonists, UVI 2112 and UVI 3003, with that of the agonist, 9-cis-retinoic acid, upon binding to the human retinoid X receptor alpha ligand-binding domain (hRXRalpha LBD) homodimer. Analysis of the H/D content by mass spectrometry showed that in comparison to 9-cis-retinoic acid, the antagonists provide much greater protection toward deuterium exchange-in throughout the protein, suggesting that the protein-antagonist complex adopts a more restricted conformation or ensemble of conformations in which solvent accesses to amide protons are reduced. A comparison between the two antagonists shows that UVI 3003 is more protective in the C-terminal region due to the extra hydrophobic interactions derived from the atoms in the benzene ring of the carboxylic acid chain. It was less protective within regions comprising peptides 271-278 and 326-330 due to differences in conformational orientation, and/or shorter carboxylic acid chain length. Decreased deuterium exchange-in in the segment 234-239 where the residues do not involve interactions with the ligand was observed with the two antagonists, but not with 9-cis-RA. The amide protons of helix 12 of the agonist- or antagonist-occupied protein in solution have the same deuterium exchange rates as the unliganded protein, supporting a suggestion made previously that helix 12 can cover the occupied binding cavity only with the cofactor present to adjust its location.     

Effect of denervation and tenotomy on slow and fast muscles of the chicken

Summary Changes of muscle weights, fiber diameters and ultrastructure were studied in the slow anterior latissimus dorsi (ALD) and in the fast posterior latissimus dorsi (PLD) of the chick three weeks after denervation and tenotomy, and after combined denervation and tenotomy of the two muscles.The slow ALD muscle becomes hypertrophic after denervation (Feng, Jung and Wu, 1962). Three weeks after nerve section, wet weights of ALD muscles are increased by 60% and fiber diameters become by 30% larger than those of contralateral control muscles. In spite of this hypertrophy, degenerative changes are seen in the ultrastructure, similar to those described in denervated atrophic muscles. Areas of dedifferentiation with autophagic vacuoles and aggregates of tubules are found in superficial layers of some fibers. Disintegration of Z lines and filaments along one or two sarcomeres occurs in a number of myofibrils, especially in muscles of young animals.In contrast to denervation alone, simultaneous denervation and tenotomy of the ALD muscles results in atrophy. Decrease of muscle weights and reduction of fiber diameters are similar as after tenotomy; in both cases muscle fibers waste by degeneration and atrophy of myofibrils.The fast PLD muscles underwent extensive atrophy in all three series of experiments. Corresponding atrophic and degenerative changes of ultrastructure were found in all instances.The authors wish to acknowledge gratefully the skillful technical assistance of Mrs. M. Sobotková and Ing. M. Doubek, and editorial assistance of Miss Virginia Hamilton.     

中国花楸属植物的分布及研究现状

花楸属(Sorbus L.)植物冠形多态、花色秀美、果实缤纷、四季叶色各异，具有很高的园艺观赏价值，但因属下种间杂交、多倍化和无融合生殖的存在，所以花楸属也是分类学上比较困难的一个类群。该研究通过细致整理和分析国家标本资源库和全球数字化植物标本数据库中花楸属植物标本信息，了解中国花楸属物种采集位置和野生种质资源的分布中心，构建中国花楸属植物标本数据库，为全国第一次林草种质资源的普查与收集提供参考；在明晰花楸属植物资源分布位置和生境的基础上，发现中国花楸属植物资源居世界之首且花楸属物种多分布在高海拔区域，尤其是在中国西南部的山区，分布有一半以上的中国花楸属物种，在该区域花楸属物种多种倍性并存、杂交频繁发生。然而，这是否为该属植物物种多样性丰富的关键因素，把高海拔分布的花楸属物种引种到低海拔区域能否适应以及如何适应低海拔的夏季高温尚不清楚。基于此，作者就自己的专业领域进一步检索了花楸属植物在形态分类与系统发育、适应性进化和保护遗传学、植物资源利用等方面的研究现状，梳理出花楸属植物目前研究尚未解决的问题，并进一步指出未来研究需重点关注的方向。建议未来的研究重点关注以下问题：(1)在坚实的系统...     

Association of chlorophyll a/b-binding Pcb proteins with photosystems I and II in Prochlorothrix hollandica

Action spectra for photosystem II (PSII)-driven oxygen evolution and of photosystem I (PSI)-mediated H₂ photoproduction and photoinhibition of respiration were used to determine the participation of chlorophyll (Chl) a/b-binding Pcb proteins in the functions of pigment apparatus of Prochlorothrix hollandica. Comparison of the in situ action spectra with absorption spectra of PSII and PSI complexes isolated from the cyanobacterium Synechocystis 6803 revealed a shoulder at 650 nm that indicated presence of Chl b in the both photosystems of P. hollandica. Fitting of two action spectra to absorption spectrum of the cells showed a chlorophyll ratio of 4:1 in favor of PSI. Effective antenna sizes estimated from photochemical cross-sections of the relevant photoreactions were found to be 192 ± 28 and 139 ± 15 chlorophyll molecules for the competent PSI and PSII reaction centers, respectively. The value for PSI is in a quite good agreement with previous electron microscopy data for isolated Pcb-PSI supercomplexes from P. hollandica that show a trimeric PSI core surrounded by a ring of 18 Pcb subunits. The antenna size of PSII implies that the PSII core dimers are associated with ∼ 14 Pcb light-harvesting proteins, and form the largest known Pcb-PSII supercomplexes.