Hypertension of renal origin: evidence for two different mechanisms   总被引：7，自引：0，他引：7  

H R Brunner  J D Kirshman  J E Sealey  J H Laragh 《Science (New York, N.Y.)》1971,174(16):1344-1346

Antibody to angiotensin 11, or a specific peptide competitive inhibitor of angiolensin II, was used to investigate the role of the renin-angiotensin system in two types of renal hypertension in rats. The data indicate that angiotensin II is in fact critically involved in the pathogenesis of the form of renal hypertension in which one renal artery is clamped and the contralateral kidney is left in place, but that it probably plays no significant role in the maintenance of experimental renal hypertension in which the opposite kidney has been removed.  相似文献   

Angiotensin-sodium interaction in blood pressure maintenance of renal hypertensive and normotensive rats   总被引：6，自引：0，他引：6  

H Gavras  H B Brunner  E D Vaughan  J H Laragh 《Science (New York, N.Y.)》1973,180(93):1369-1371

A specific inhibitor of angiotensin II was used in rats to investigate whether angiotensin is involved in the maintenance of blood pressure in one-kidney Goldblatt hypertension, in which plasma renin levels are not usually increased. The inhibitor produced marked falls in blood pressure, often down to normal levels in the hypertensive animals only when they were depleted in sodium and not after sodium repletion. Much lesser but still significant falls in blood pressure were also produced in normotensive sodium-depleted rats but not in repleted rats. We conclude that the importance of angiotensin for maintaining blood pressure is largely determined by its relation to available sodium or fluid volume, since the renin component in maintenance of either the hypertensive or the normotensive state could be exposed only by sodium deprivation. Therefore, volume expansion per se or other pressor factors may be involved in maintaining blood pressure of these sodium-replete normotensive or hypertensive animals.  相似文献   

Teaching. Opportunities to learn in America's elementary classrooms     

Pianta RC  Belsky J  Houts R  Morrison F;National Institute of Child Health  Human Development 《Science (New York, N.Y.)》2007,315(5820):1795-1796

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G protein signalling involved in host recognition and mycoparasitismrelated chitinase expression in Trichoderma atroviride          下载免费PDF全文

Susanne Zeilinger　 Barbara Reithner　 Kurt Brunner　 Valeria Scala　 Isabel Peiβl　 Matteo Lorito　 Robert L Mach 《浙江大学学报(农业与生命科学版)》2004,30(4):448-448

Mycoparasitic species of Trichoderma are commercially applied as biological control agents against various fungal pathogens. The mycoparasitic interaction is host specific and includes recognition, attack and subsequent penetration and killing of the host. Investigations on the underlying events revealed that Trichoderma responds to multiple signals from the host (e.g. lectins or other ligands such as low molecular weight components released from the host's cell wall) and host attack is ac…  相似文献   

Bioaccumulation of melamine in catfish muscle following continuous, low-dose, oral administration     

Andersen WC  Turnipseed SB  Karbiwnyk CM  Evans E  Hasbrouck N  Mayer TD  Gieseker CM  Nochetto C  Stine CB  Reimschuessel R 《Journal of agricultural and food chemistry》2011,59(7):3111-3117

In this study, catfish muscle was analyzed for melamine (MEL) and cyanuric acid (CYA) residues following experimental feeding with low doses of MEL and MEL and CYA (MEL+CYA) and with the insoluble melamine-cyanurate complex (MEL=CYA). Catfish were daily fed 0.1 mg/kg BW of MEL for 15, 28, or 42 days, 0.1 mg/kg BW of MEL+CYA for 28 days, 2.5 mg/kg BW of MEL+CYA for 14 days, or 400 mg/kg BW of MEL=CYA for 3 days. Residues in the tissue were determined by LC-MS/MS. MEL was extracted with acidic acetonitrile, followed by defatting with dichloromethane, and isolated with cation exchange solid phase extraction (SPE). For CYA analysis, fish were extracted with dilute acetic acid, defatted with hexane, and cleaned up with a graphitic carbon SPE. Catfish fed 0.1 mg/kg BW of MEL reached a maximum muscle residue concentration of 0.33 ± 0.04 mg/kg (ppm) after 28 days of continuous feeding. The same concentration was found for MEL+CYA feeding at the 0.1 mg/kg BW level for 28 days. Feeding at 2.5 mg/kg BW of MEL+CYA yielded muscle concentrations above the 2.5 mg/kg level of concern for most of the study fish. Finally, catfish fed high levels of the MEL=CYA complex (400 mg/kg BW) accumulated relatively little MEL in the muscle (0.14 ± 0.07 mg/kg) and, unlike treatment with MEL+CYA, did not form renal melamine-cyanurate crystals. Appreciable concentrations of CYA were not detected in any of the muscles tested. These studies provide data to model the bioaccumulation of triazine residues into edible fish tissue as a result of the continuous consumption of adulterated feed.  相似文献   

Kinetics of jump landing in agility dogs     

Pfau T  Garland de Rivaz A  Brighton S  Weller R 《Veterinary journal (London, England : 1997)》2011,190(2):278-283

A recent survey reported an increased risk of injury in dogs participating in agility, a competitive canine sport involving different jumping activities. The aim of this study was to quantify the kinetic parameters during jump landing for commonly used obstacle types. It was hypothesised that with increasing obstacle height, the vertical force and vertical and accelerative horizontal impulse will increase as a result of a lengthened aerial phase, a more acute landing angle and the need to convert potential into forwards kinetic energy. Simultaneous kinetic and kinematic data were recorded from 11 competition agility dogs jumping over obstacle combinations of different height and inter-obstacle distance. Speed and landing angle of the second of the two consecutive jumps were successfully controlled by obstacle height and distance between obstacles. Statistical analysis showed differences between obstacles for peak vertical force, vertical impulse and accelerative horizontal impulse (increasing values with more acute landing angles). Extremely high peak vertical force was observed in the forelimbs (4.5 times bodyweight) when landing from a hurdle jump at high speed. Further detailed studies into the consequences for internal limb structures are warranted in order to clarify how this might be related to injury.  相似文献   

Effects of root exudates and humic substances on weathering kinetics     

Michael Ochs  Ivano Brunner  Werner Stumm  BoŽena ćosović 《Water, air, and soil pollution》1993,68(1-2):213-229

The effect of complex natural organic ligands on the weathering kinetics of aluminum oxide was investigated in laboratory experiments. A peat-derived humic substance and root exudates obtained from ectomycorrhizal (Picea abies — Hebeloma crustuliniforme) and non-mycorrhizal Norway Spruce trees; and γ-Al₂O₃ were used as a model system. The experimental weathering rates are in accordance with a surface-controlled dissolution mechanism. The effect of the humic material on dissolution rates appears to depend on the degree of protonation of the humic (macro)molecules: we observed dissolution-enhancement or -inhibition at pH 3 and 4, respectively. Ectomycorrhizal exudates proved to be effective weathering agents at pH 4, as opposed to humic material and non-mycorrhizal exudates. Our results suggest that (i) the role of humic materials in mineral weathering and podzolization is different from what is commonly thought, and (ii) mineral weathering rates in the rhizosphere may be higher than in the bulk soil.  相似文献   

The environmental safety of eprinomectin to earthworms     

Halley BA  Winter R  Yoon S  Marley SE  Rehbein S 《Veterinary parasitology》2005,128(1-2):109-114

A study was conducted to assess the environmental safety of the endectocide eprinomectin to the earthworm Lumbricus terrestris under conditions mimicking typical product use on pasture. The LC50 value of eprinomectin in artificial soil after 28 days of exposure is higher than the levels expected in feces from dosed cattle or in soil fertilized with manure from dosed cattle, which indicates a wide margin of safety for this compound to earthworms. However, the no-observed-effect concentration has not been established. Therefore, the current study was conducted to determine whether there would be any effects on earthworms from feces from cattle treated with the commercial formulation of eprinomectin. Feces were collected rectally from grazing cattle on Day 0 before treatment and on Days 2, 4, 7 and 14 after treatment with EPRINEX (eprinomectin) Pour-On for Beef and Dairy Cattle (Merial Limited) at 0.5 mg eprinomectin per kg bodyweight. Assays of eprinomectin B1a (the major component of eprinomectin) were 0, 0.427, 0.152, 0.0512 and 0.00185 mg kg-1 wet weight of feces (equivalent to 0, 3.34, 1.19, 0.40 and 0.010 mg kg-1 on a dry weight basis, respectively). No significant differences (p>0.05) were observed at any day post-treatment in the survival or behavioral effects of any worms fed post-dose feces relative to the worms fed control feces. All post-dose comparisons of weight changes of living earthworms to the control group were not significantly different (p>0.05), indicating that treatment of cattle with EPRINEX (eprinomectin) Pour-On for Beef and Dairy Cattle did not affect feeding or weight gain of the earthworms. The LC50 value and the results of this study establish the wide margin of safety afforded to earthworms by eprinomectin under typical usage conditions.  相似文献   

Routes of transmission and consequences of small ruminant lentiviruses (SRLVs) infection and eradication schemes     

Peterhans E  Greenland T  Badiola J  Harkiss G  Bertoni G  Amorena B  Eliaszewicz M  Juste RA  Krassnig R  Lafont JP  Lenihan P  Pétursson G  Pritchard G  Thorley J  Vitu C  Mornex JF  Pépin M 《Veterinary research》2004,35(3):257-274

Small ruminant lentiviruses (SRLV = maedi-visna in sheep and caprine arthritis encephalitis in goats) are distributed throughout most countries of the world, particularly Europe. Laboratories from 16 European countries established collaborations within the framework of a COST (CO-operation in the field of Scientific and Technical Research) action sponsored by the European Union in order to (i) better organize their research programmes on SRLVs and (ii) to coordinate efforts to combat these two diseases. After five years, a consensus conference--the first one in the veterinary medicine field--concluded the work of this network of laboratories by reviewing the present position and discussing three important questions in the field of SRLVs: routes of transmission, consequences of infection and potential role of eradication programmes at either a European or local level, according to the situation in each country or region. This paper brings together existing information regarding these questions and identifies areas for future research.  相似文献   

Frequency of mutations associated with fungicide resistance and population structure of <Emphasis Type="Italic">Mycosphaerella graminicola</Emphasis> in Tunisia     

Sameh Boukef  Bruce A. McDonald  Amor Yahyaoui  Salah Rezgui  Patrick C. Brunner 《European journal of plant pathology / European Foundation for Plant Pathology》2012,132(1):111-122

The occurrence of fungicide resistance in Mycosphaerella graminicola populations from Tunisia was investigated by examining mutations known to be associated with strobilurin and azole resistance. Few mutations associated with fungicide resistance were detected. No evidence for strobilurin resistance was found among 357 Tunisian isolates and only two among 80 sequenced isolates carried mutations associated with azole resistance. A network analysis suggested that these mutations emerged independently from mutations found in previously described European populations. The population genetic structure of M. graminicola in Tunisia was analyzed using variation at 11 microsatellite loci. Populations in Tunisia were characterized by high gene and genotype diversity. All populations were in gametic equilibrium and mating type proportions did not deviate from the 1:1 ratio expected under random mating, consistent with regular cycles of sexual reproduction. In combination with a high degree of gene flow among sampling sites, M. graminicola must be considered a pathogens with high evolutionary potential. Thus, control strategies against Septoria blotch in Tunisia should be optimized to reduce the emergence and spread of resistant isolates.  相似文献