Determination of intracellular reactive oxygen species and high mitochondrial membrane potential in Percoll-treated viable boar sperm using fluorescence-activated flow cytometry     

Guthrie HD  Welch GR 《Journal of animal science》2006,84(8):2089-2100

The use of frozen semen in the swine industry is limited by problems with viability and fertility compared with liquid semen. Part of the reduction in sperm motility and fertility associated with cryopreservation may be due to oxidative damage from excessive or inappropriate formation of reactive oxygen species (ROS). Chemiluminescence measurements of ROS are not possible in live cells and are problematic because of poor specificity. An alternative approach, flow cytometry, was developed to identify viable boar sperm containing ROS utilizing the dyes hydroethidine and 2', 7'-dichlorodihydrofluorescein diacetate as oxidizable substrates and impermeant DNA dyes to exclude dead sperm. The percentage of sperm with high mitochondrial transmembrane potential was determined by flow cytometry using the mitochondrial probe 5, 5', 6, 6'-tetrachloro-1, 1', 3, 3'-tetraethylbenzimidazolylcarbocyanine iodide with propidium iodide staining to exclude nonviable cells. Sperm were incubated with and without ROS generators and free radical scavengers. Basal ROS formation was low (less than 4%) and did not differ (P = 0.26) between viable fresh and frozen-thawed boar sperm. In addition, fresh and frozen-thawed viable sperm were equally susceptible (P = 0.20) to intracellular formation of ROS produced by xanthine/xanthine oxidase (94.4 and 87.9% of sperm, respectively). Menadione increased (P < 0.05) ROS formation, decreased (P < 0.05) JC-1-aggregate fluorescence intensity, and decreased (P < 0.05) motion variables by 25 to 60%. The mechanism of inhibition of motility by ROS formation may be related to a decrease in mitochondrial charge potential below a critical threshold. Catalase and superoxide dismutase treatment in the presence of xanthine/xanthine oxidase indicated that hydrogen peroxide was the primary intracellular ROS measured. Further, catalase, but not superoxide dismutase, was capable of attenuating ROS-induced inhibition of motility. Whereas basal intracellular hydrogen peroxide formation was low in viable fresh and frozen-thawed boar sperm, both were quite susceptible to external sources of hydrogen peroxide.  相似文献   

Dynamic nuclear actin assembly by Arp2/3 complex and a baculovirus WASP-like protein     

Goley ED  Ohkawa T  Mancuso J  Woodruff JB  D'Alessio JA  Cande WZ  Volkman LE  Welch MD 《Science (New York, N.Y.)》2006,314(5798):464-467

Diverse bacterial and viral pathogens induce actin polymerization in the cytoplasm of host cells to facilitate infection. Here, we describe a pathogenic mechanism for promoting dynamic actin assembly in the nucleus to enable viral replication. The baculovirus Autographa californica multiple nucleopolyhedrovirus induced nuclear actin polymerization by translocating the host actin-nucleating Arp2/3 complex into the nucleus, where it was activated by p78/83, a viral Wiskott-Aldrich syndrome protein (WASP)-like protein. Nuclear actin assembly by p78/83 and Arp2/3 complex was essential for viral progeny production. Recompartmentalizing dynamic host actin may represent a conserved mode of pathogenesis and reflect viral manipulation of normal functions of nuclear actin.  相似文献   

The Effect of Poisonous Range Plants on Abortions in Livestock     

Kevin D. Welch  T. Zane Davis  Kip E. Panter  James A. Pfister  Benedict T. Green 《Herpetological Monographs》2009,31(1):28-34

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A synthesis of the coast‐wide decline in survival of West Coast Chinook Salmon (Oncorhynchus tshawytscha,Salmonidae)     

David Warren Welch  Aswea Dawn Porter  Erin Leanne Rechisky 《Fish and Fisheries》2021,22(1):194-211

We collated smolt‐to‐adult return rate (SAR) data for Chinook salmon from all available regions of the Pacific coast of North America to examine the large‐scale patterns of salmon survival. For consistency, our analyses primarily used coded wire tag‐based (CWT) SAR estimates. Survival collapsed over the past half century by roughly a factor of three to ca. 1% for many regions. Within the Columbia River, the SARs of Snake River populations, often singled out as exemplars of poor survival, are unexceptional and in fact higher than estimates reported from many other regions of the west coast lacking dams. Given the seemingly congruent decline in SARs to similar levels, the notion that contemporary survival is driven primarily by broader oceanic factors rather than local factors should be considered. Ambitious Columbia River rebuilding targets may be unachievable because other regions with nearly pristine freshwater conditions, such as SE Alaska and northern BC, also largely fail to reach these levels. Passive integrated transponder (PIT) tag‐based SAR estimates available for Columbia River Basin populations are generally consistent with CWT findings; however, PIT tag‐based SARs are not adjusted for harvest which compromises their intended use because harvest rates are large and variable. More attention is needed on how SARs should be quantified and how rebuilding targets are defined. We call for a systematic review by funding agencies to assess consistency and comparability of the SAR data generated and to further assess the implications of survival falling to similar levels in most regions of the west coast.  相似文献   

CONTRIBUTION OF BRYN MAWR COLLEGE TO THE HIGHER EDUCATION OF WOMEN     

Welch WH 《Science (New York, N.Y.)》1922,56(1436):1-8

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一起仔猪水肿病的诊疗     

高多凤 《中国兽药杂志》2005,39(10):50-50

2003年10月,我县某养猪专业户自繁自养的9头70日龄仔猪,突然发生一种以头部水肿、共济失调、惊厥和麻痹为特征的疫病,经临床检查、剖检变化、实验室检验确诊为仔猪水肿病.  相似文献   

Axial Characteristics of Circular External Skeletal Fixator Single Ring Constructs     

Daniel D. Lewis  DVM  Diplomate ACVS    Dwight G. Bronson  MS    Alan R. Cross  DVM  Diplomate ACVS    Robert D. Welch  DVM  PhD  Diplomate ACVS    Paul S. Kubilis  MS 《Veterinary surgery : VS》2001,30(4):386-394

OBJECTIVE: Evaluate the effects of varying ring diameter, wire tension, and wire-divergence angle on the axial stiffness characteristics of circular external skeletal fixator single-ring constructs. Study Design-Biomechanical evaluation using circular fixator components and a Delrin cylinder bone model. METHODS: Single ring constructs using two 1.6 mm diameter Kirschner wires to secure a 19 mm Delrin cylinder centered within the ring were examined. Component variables evaluated were ring diameter (50 mm, 66 mm, 84 mm, and 118 mm), wire-divergence angle (30 degrees, 60 degrees, and 90 degrees ), and wire tension (0 kg, 30 kg, 60 kg, and 90 kg). A total of 48 constructs were examined. Rings were rigidly mounted on a universal testing system and the cylinder loaded in axial compression (7.4 N/s) to 220 N. Load/displacement curves were analyzed to determine the following: the displacement (mm) that occurred before the slope of each load/displacement curve became linear, the stiffness (N/mm) of the linear portion of each load/deformation curve, and the total displacement (mm) produced at maximal load. Least-squares linear regression was used to model response variables as linear functions of ring diameter, wire divergence angle, and wire tension. Three-way interactions and 2-way interactions among independent component variables were evaluated first in the modeling process and included in a best model if response variables were found to have statistically significant regression coefficients. The regression coefficients and corresponding standard errors and covariances were used to estimate the maximal effect and standard error attributable to wire divergency angle (change from 30 degrees to 90 degrees ) and wire tension (change from 0 to 90 kg) for each ring diameter. RESULTS: All load/deformation curves had an initial exponential increase in stiffness, with the slope becoming linear at higher loads. The exponential phase was more pronounced in larger-diameter ring constructs and was mitigated by tensioning the wires. Ring diameter had the greatest influence on displacement that occurred before the curve became linear (semipartial r(2) [sp-r2] = .89), stiffness (sp-r2 = .94), and total displacement (sp-r2 = .93). Wire tension exerted a smaller influence on displacement that occurred before the curve became linear (sp-r2 =.06), stiffness (sp-r2 = .03), and total displacement (sp-r2 = .05). Wire divergence angle had a nominal effect on displacement that occurred before the curve became linear (sp-r2 = .0001), on stiffness (sp-r2 = .004), and on total displacement (sp-r2 =.003). CONCLUSIONS: Ring diameter had a profound effect on the axial stiffness characteristic of single ring constructs. Tensioning of the fixation wires can improve the axial stiffness characteristics of these constructs, particularly in larger diameter ring constructs, by mitigating the initial exponential phase of the load/deformation curve. Wire divergence angle had only a nominal differential effect on axial stability. CLINICAL RELEVANCE: Understanding how individual component variables and their interactions influence bone segment stability should help surgeons to optimize interfragmentary strain. Tensioning fixation wires is probably unnecessary in 50 mm diameter ring constructs, but assumes greater importance as ring diameter increases.  相似文献   

AP—Animal Production Technology: Predicting Sensor Placement Targets on Pigs using Image Analysis     

R. D. Tillett  A. R. Frost  S. K. Welch 《Biosystems Engineering》2002,81(4):453

This work forms part of a longer-term project aimed at developing a robot to bring a sensor into contact with an animal. The example application is to place an ultrasonic sensor onto the back of a pig as it uses a feeding stall. This paper presents the accuracy required in placing the sensor, and the accuracy of target location achieved using a linear function of landmark points on the pig outline, located by image analysis.The P2 standard position is close to a local minimum in fat thickness. When the target is chosen to be 25 mm ahead of the last rib and 50 mm from the mid-line of the pig, then a positional error of ±10 mm laterally and ±25 mm longitudinally will give a backfat measurement within 5% of the minimum.A linear model predicting the target position from six points on the outline was trained on 7549 images and tested on 2978 images. On the test data the root means square (r.m.s.) errors in the X and Y directions were 16 and 38 mm, respectively. A linear model with separate offset terms in X and Y coordinates for each sequence gave r.m.s. errors of 6 and 8 mm. However, this requires the offset value to be calculated for each sequence. An active system is proposed where multiple measurements from each pig will be used to improve the backfat estimate to within 5% of the minimum value.  相似文献   

The composition of precipitation at Snoqualmie Pass and Stevens Pass in the Central Cascades of Washington state     

L. Clint Duncan  E. B. Welch  Wally Ausserer 《Water, air, and soil pollution》1986,30(1-2):217-229

Bulk precipitation samples were collected weekly during the winters of 1984 and 1985 at two high elevation sites in the Washington Cascades. The Puget basin, west and upwind of the Cascade sites, includes an urban industrialized region with a variety of area and point sources of acidic oxides. The precipitation was found to be low in contaminant content with SO₄ ⁼ and NO₃ ^? concentrations as low or lower than those reported for remote pristine stations in the US or elsewhere. It is suggested that the reduced contaminant levels result from an interplay of the meteorological and washout factors unique to the region.  相似文献   

Plasma levels of six carotenoids in nine European countries: report from the European Prospective Investigation into Cancer and Nutrition (EPIC)     

Al-Delaimy WK  van Kappel AL  Ferrari P  Slimani N  Steghens JP  Bingham S  Johansson I  Wallström P  Overvad K  Tjønneland A  Key TJ  Welch AA  Bueno-de-Mesquita HB  Peeters PH  Boeing H  Linseisen J  Clavel-Chapelon F  Guibout C  Navarro C  Quirós JR  Palli D  Celentano E  Trichopoulou A  Benetou V  Kaaks R  Riboli E 《Public health nutrition》2004,7(6):713-722

BACKGROUND: In addition to their possible direct biological effects, plasma carotenoids can be used as biochemical markers of fruit and vegetable consumption for identifying diet-disease associations in epidemiological studies. Few studies have compared levels of these carotenoids between countries in Europe. OBJECTIVE: Our aim was to assess the variability of plasma carotenoid levels within the cohort of the European Prospective Investigation into Cancer and Nutrition (EPIC). METHODS: Plasma levels of six carotenoids--alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein and zeaxanthin--were measured cross-sectionally in 3043 study subjects from 16 regions in nine European countries. We investigated the relative influence of gender, season, age, body mass index (BMI), alcohol intake and smoking status on plasma levels of the carotenoids. RESULTS: Mean plasma level of the sum of the six carotenoids varied twofold between regions (1.35 micromol l(-1) for men in Malm?, Sweden vs. 2.79 micromol l(-1) for men in Ragusa/Naples, Italy; 1.61 micromol l(-1) for women in The Netherlands vs. 3.52 micromol l(-1) in Ragusa/Naples, Italy). Mean levels of individual carotenoids varied up to fourfold (alpha-carotene: 0.06 micromol l(-1) for men in Murcia, Spain vs. 0.25 micromol l(-1) for vegetarian men living in the UK). In multivariate regression analyses, region was the most important predictor of total plasma carotenoid level (partial R(2)=27.3%), followed by BMI (partial R(2)=5.2%), gender (partial R(2)=2.7%) and smoking status (partial R(2)=2.8%). Females had higher total carotenoid levels than males across Europe. CONCLUSIONS: Plasma levels of carotenoids vary substantially between 16 different regions in Italy, Greece, Spain, France, Germany, the UK, Sweden, Denmark and The Netherlands. Compared with region of residence, the other demographic and lifestyle factors and laboratory measurements have limited predictive value for plasma carotenoid levels in Europe.  相似文献