Early epithelial invasion by Salmonella enterica serovar Typhimurium DT104 in the swine ileum     

Meyerholz DK  Stabel TJ  Ackermann MR  Carlson SA  Jones BD  Pohlenz J 《Veterinary pathology》2002,39(6):712-720

Salmonella enterica serovar Typhimurium is an important intestinal pathogen in swine. This study was performed to document the early cellular invasion of Salmonella serovar Typhimurium in swine ileum. Ileal gut-loops were surgically prepared in ten 4- to 5-week-old mixed-breed pigs and inoculated for 0-60 minutes. Loops were harvested and prepared for both scanning and transmission electron microscopy (SEM and TEM, respectively). Preferential bacterial adherence to microfold cells (M cells) was seen within 5 minutes, and by 10 minutes bacterial invasion of the apical membrane was seen in M cells, goblet cells, and enterocytes. This multicellular invasion was observed throughout the course of infection. In addition, SEM revealed a specific affinity of Salmonella serovar Typhimurium to sites of cell extrusion. Using TEM, bacteria in these areas were focused in the crevices formed by the extruding cell and the adjacent cells and in the cytoplasm immediately beneath the extruding cell. Our results suggest that early cellular invasion by Salmonella serovar Typhimurium is nonspecific and rapid in swine. Furthermore, the combination of SEM and TEM data suggests that Salmonella serovar Typhimurium may use sites of cell extrusion as an additional mechanism for early invasion.  相似文献   

Toxicological and mechanistic studies on neonicotinoid cross resistance in Q-type Bemisia tabaci (Hemiptera: Aleyrodidae)     

Nauen R  Stumpf N  Elbert A 《Pest management science》2002,58(9):868-875

The tobacco whitefly, Bemisia tabaci Gennadius (Homoptera: Aleyrodidae) is a serious pest in numerous cropping systems and has developed a high degree of resistance against several chemical classes of insecticides. One of the latest group of insecticides introduced to the market were the neonicotinoids (chloronicotinyls), acting agonistically on insect nicotinic acetylcholine receptors. Resistance to neonicotinoid insecticides has recently been shown to occur, especially in Q-type B tabaci in some places in Almeria, Spain, whereas control of B-type B tabaci in many other intense cropping systems worldwide has remained on high levels. Our study revealed that neonicotinoid-resistant Q-type strains from Almeria were often more than 100-fold less susceptible to thiamethoxam, acetamiprid and imidacloprid when tested in discontinuous systemic laboratory bioassays. The resistance factors were generally 2- to 3-fold lower in leaf-dip bioassays. In addition to the Spanish strains, we obtained two other highly neonicotinoid-cross-resistant B tabaci greenhouse populations, one from Italy (December 1999) and one from Germany (June 2001). A molecular diagnostic analysis revealed that both strains also belong to the (Spanish) subtype Q of the B tabaci species complex. The resistance levels of Q-type whitefly strains derived from Almeria greenhouses in 1999 remained stable for at least two years, even when maintained in the laboratory without any selection pressure. The biochemical mechanisms conferring resistance to neonicotinoids have not yet been elucidated in detail, but synergist studies suggested a possible involvement of microsomal monooxygenases. Furthermore, we checked two Almerian strains of B tabaci isolated in 1998 and 1999 and demonstrated that neonicotinoid resistance is not due to an altered [3H]imidacloprid binding site of nicotinic acetylcholine receptors.  相似文献   

Restoration and stress relief through physical activities in forests and parks   总被引：2，自引：0，他引：2  

Ralf Hansmann  Stella-Maria Hug  Klaus Seeland 《Urban Forestry & Urban Greening》2007,6(4):213-225

A field survey assessed the restorative effects of visiting an urban forest and a city park in Zurich, Switzerland. Respondents rated their headaches, level of stress, and how balanced they felt both prior to visiting the outdoor location and at the time of being interviewed. Suffering from headaches and stress decreased significantly, and feeling well-balanced increased significantly. The recovery ratio for stress was 87%, and the reduction in headaches was 52%, in terms of the possible improvements on five-point rating scales. With respect to feeling well-balanced, the observed changes amounted to 40% of the possible enhancement. Positive effects increased with length of visit, and individuals practising sports (e.g., jogging, biking, playing ball) showed significantly higher improvements than those engaged in less strenuous activities (e.g., taking a walk or relaxing). These findings support previous research on how exercise in green spaces promotes well-being and recovery from stress.  相似文献   

Evaluation of three different point‐of‐care tests for quantitative measurement of canine C‐reactive protein          下载免费PDF全文

Anne‐Katherine Jasensky  Stefanie Klenner  Ralf Einspanier  Barbara Kohn 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2015,44(2):205-214

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Effect of Oil Overlay on Inhibition Potential of Roscovitine in Sheep Cumulus‐Oocyte Complexes          下载免费PDF全文

LF Crocomo  WC Marques Filho  CMV Ulian  NS Branchini  DT Silva  CL Ackermann  FC Landim‐Alvarenga  SD Bicudo 《Reproduction in domestic animals》2015,50(3):410-416

Inhibitors of cyclin‐dependent kinases, as roscovitine, have been used to prevent the spontaneous resumption of meiosis in vitro and to improve the oocyte developmental competence. In this study, the interference of oil overlay on the reversible arrest capacity of roscovitine in sheep oocytes as well as its effects on cumulus expansion was evaluated. For this, cumulus‐oocyte complexes (COCs) were cultured for 20 h in TCM 199 with 10% foetal bovine serum (Control) containing 75 μm roscovitine (Rosco). Subsequently, they were in vitro matured (IVM) for further 18 h in inhibitor‐free medium with LH and FSH. The culture was performed in Petri dishes under mineral oil (+) or in 96 well plates without oil overlay (?) at 38.5°C and 5% CO₂. At 20 and 38 h, the cumulus expansion and nuclear maturation were evaluated under stereomicroscope and by Hoechst 33342 staining, respectively. No group presented cumulus expansion at 20 h. After additional culture with gonadotrophins, a significant rate of COCs from both Control groups (+/?) exhibited total expansion while in both Rosco groups (+/?) the partial expansion prevailed. Among the oocytes treated with roscovitine, 65.2% were kept at GV in the absence of oil overlay while 40.6% of them reached MII under oil cover (p < 0.05). This meiotic arrest was reversible, and proper meiosis progression also occurred in the Control groups (+/?). So, the culture system without oil overlay improved the meiotic inhibition promoted by roscovitine without affecting the cumulus expansion rate or the subsequent meiosis progression.  相似文献   

Erythema multiforme associated with zonisamide in a dog          下载免费PDF全文

Amanda L. Ackermann  Linda A. Frank  Michael F. McEntee  Elizabeth R. May 《Veterinary dermatology》2015,26(5):391-e89

This report describes a dog that developed erythema multiforme in temporal association with administration of the sulphonamide‐based anticonvulsant drug zonisamide. Similar adverse drug reactions have been associated with sulphonamide antimicrobial drugs. Caution should be exercised when prescribing this medication for dogs with known hypersensitivity to sulphonamides.  相似文献   

Nonthymoma‐associated exfoliative dermatitis in 18 cats          下载免费PDF全文

Monika Linek  Silvia Rüfenacht  Chiara Brachelente  Claudia von Tscharner  Claude Favrot  Sylvia Wilhelm  Claudia Nett  Ralf S. Mueller  Ursula Mayer  Monika Welle 《Veterinary dermatology》2015,26(1):40-e13

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Insecticide resistance in disease vectors of public health importance   总被引：3，自引：0，他引：3  

Nauen R 《Pest management science》2007,63(7):628-633

Vector-borne diseases are a global problem--a trend that may only increase if global temperature rises and demographic trends continue--and their economic and social impact are enormous. Insecticides play a vital role in the fight against these diseases by controlling the vectors themselves in order to improve public health; however, resistance to commonly used insecticides is on the rise. This perspective outlines the major classes of disease vector control agents and the mechanisms of resistance that have evolved, arguing that effective resistance management strategies must carefully monitor resistance in field populations and use combinations of the limited modes of action available to best effect. Moreover, the development of novel insecticide classes for control of adult mosquitoes and other vectors becomes increasingly important.  相似文献   

Binding and bioactivity of insulin in primary cultures of carp (Cyprinus carpio) hepatocytes     

Helmut Segner  Ralf Böhm  Werner Kloas 《Fish physiology and biochemistry》1993,11(1-6):411-420

Isolated carp hepatocytes cultured in serum-free, chemically defined medium were used to investigate within the same cell preparation characteristics of the binding of insulin as well as effects of insulin on cellular metabolism. The binding of human [¹²⁵I]-insulin to carp hepatocytes was studied in kinetic, saturation and displacement experiments. A dependency of insulin binding on the collagenase used for cell isolation was demonstrated. Insulin binding decreased during the first 12h of culture but remained constant during the following 12h. The kinetic experiments revealed that [¹²⁵I]-insulin binding reached a steady state within 20–30 min of incubation. The mathematical analysis of the saturation experiments demonstrated the existence of two populations of binding sites, one with high affinity (K_d1 = 5.5 pM) and low capacity (B_max1 = 0.14 fmol/mg protein or 77 binding sites/cell) and one with low affinity (K_d2 = 2.4 nM) and high capacity (B_max2 = 17.6 fmol/mg protein or 9623 binding sites/cell). In competition experiments, 312 pM [¹²⁵I]-insulin was displaced by cold insulin, IGF-I and IGF-II with IC₅₀ values of 2.2, 7.9 and 20.3 nM, respectively. Glucagon was without effect. Binding of insulin to carp hepatocytes resulted in a significant reduction of glucose release and a significant increase of protein synthesis as of de novo fatty acid synthesis. dedicated to Prof. Dr. W. Hanke on the occasion of his 65^th birthday.  相似文献   

Bronchiolar metaplasia and Ulex europaeus agglutinin I (UEA-I) affinity in Mycoplasma hyopneumoniae-infected lungs of six pigs.     

M R Ackermann  M C Debey  B M Debey 《Veterinary pathology》1991,28(6):533-535

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