Vitamin K requirement and reproduction in bromadiolone-resistant Norway rats     

Jacob J  Endepols S  Pelz HJ  Kampling E  Cooper TG  Yeung CH  Redmann K  Schlatt S 《Pest management science》2012,68(3):378-385

BACKGROUND: Nucleotide polymorphisms in the VKORC1 gene can be linked to anticoagulant rodenticide resistance in Norway rats (Rattus norvegicus Berkenhout). This provides a fitness advantage to rats exposed to anticoagulant actives, but may also cause fitness costs. The vitamin K requirement and reproductive parameters of bromadiolone‐resistant rats (Westphalian resistant strain; VKOR variant Tyr139Cys) and bromadiolone‐susceptible Norway rats were compared. RESULTS: At vitamin K deficiency, blood clotting times increased in all homozygous resistant males within 8 days and in 80% of homozygous resistant females within 15 days. There was little effect on blood clotting in heterozygous males and no effect in heterozygous females and VKOR wild‐type individuals. Litter size was about 20% higher in sensitive pairs compared with resistant pairs. Testes growth, male gonad weight, sperm motility and testis cell concentration were unaffected by the mutation. CONCLUSIONS: The VKOR variant Tyr139Cys causes considerable physiological cost in Norway rats in terms of vitamin K requirement and reproduction. This may affect the distribution and spread of resistant individuals in the wild. Decreased litter size of resistant parents seems to be due to lowered female reproductive performance, as there was no significant effect of the mutation on any aspects of male reproduction considered, but this requires further study. Copyright © 2011 Society of Chemical Industry  相似文献   

Effects of ivabradine on heart rate and left ventricular function in healthy cats and cats with hypertrophic cardiomyopathy     

Riesen SC  Schober KE  Smith DN  Otoni CC  Li X  Bonagura JD 《American journal of veterinary research》2012,73(2):202-212

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In Vitro Mechanical Evaluation of a Novel Pin–Sleeve System for External Fixation of Distal Limb Fractures in Horses: A Proof of Concept Study     

Stefano Brianza  Vittoria Brighenti  Ludovic Boure  Victor Sprenger  Simon Pearce  Karsten Schwieger 《Veterinary surgery : VS》2010,39(5):601-608

Objective: To evaluate the efficacy of a novel pin–sleeve cast (PSC) system for external fixation of distal limb fractures in horses and to compare it with the transfixation pin cast (TPC) system. Study Design: Experimental. Sample Population: One bone substitute each was used for the TPC and PSC systems. The PSC was tested in 4 configurations characterized by different pin preloads. Methods: Specimens were loaded in axial compression in the elastic range. Variables compared statistically were: bone substitute axial displacement and axial strain measured above implants with strain gauges. Pin preload was correlated with the variables investigated. Load to failure and a fatigue tests supplemented the investigation. Results: The PSC configuration with the highest pin preload showed a significantly lower axial displacement compared with the TPC. No significant differences were observed between all other PSC configurations and the TPC. All PSC systems had a significant decrease in recorded strain compared with the TPC system. Pin axial preload inversely correlated with axial displacement but had no effect on axial strain. In the failure test, the PSC encountered plastic deformation earlier than the TPC. In the fatigue test, the PSC ran >200,000 cycles. Conclusions: Preliminary in vitro tests showed that the PSC system significantly reduced peri‐implant strain while concurrently having comparable axial displacement to the TPC system. Clinical Relevance: The PSC system has the potential to reduce the risk of pin loosening in horses.  相似文献   

Herpesviruses—A zoonotic threat?     

B. Karsten Tischer  Nikolaus Osterrieder 《Veterinary microbiology》2010,140(3-4):266-270

Herpesviruses are highly host specific and share a long synchronous evolution with their hosts. Only in rare cases, species barriers fall and allow animal to human or human to animal transmission. Among the zoonotic herpesviruses, Cercopithecine herpesvirus 1 is the most significant and can be transmitted from macaques to human. Conversely, Human herpesvirus 1 is capable of causing severe disease in primates. Besides those two examples, there are several herpesviruses with a certainly limited or only suspected ability to cross species barriers. Those include Saimiriine herpesvirus 2, Phocid herpesvirus 2, Equid herpesvirus 1, Epstein-Barr Virus, Marek's disease virus, and Pseudorabies virus. Concerning xenotransplantations, porcine gammaherpesviruses must be considered as a zoonotic threat.  相似文献   

Evaluation of transcutaneous Doppler ultrasonography for the measurement of blood flow in the femoral artery of pigs     

Fernández del Palacio MJ  Luis Fuentes V  Bonagura JD  Schober KE  Hatfield DG  Laughlin MH 《American journal of veterinary research》2003,64(1):43-50

OBJECTIVE: To compare measurements of blood flow in the common femoral artery obtained by duplex Doppler ultrasonography (DDU) and a reference ultrasonic transit-time flow (TTF) method and to examine the impact of Doppler spectral waveform measurement techniques on volumetric estimates. ANIMALS: 5 healthy female pigs. PROCEDURES: Femoral arterial blood flow was measured simultaneously in anesthetized pigs by use of a TTF probe (left femoral artery) and transcutaneous DDU (right femoral artery). A range of flow states was induced pharmacologically by using xylazine, bradykinin, dobutamine, and isoflurane. Volumetric blood flow was calculated from DDU waveforms, using the product of the flow velocity integral (FVI), the cross-sectional vessel area, and heart rate. Three calculations of FVI were obtained by manually tracing the Doppler spectral envelopes at the outer envelope, the modal, and the inner envelope of the spectral dispersion pattern. Data analysis included calculation of Pearson correlation coefficients and Bland-Altman limits of agreement. RESULTS: Blood flow measured by DDU was more closely correlated with TTF measurements when the modal or inner envelope tracing method was used (r, 0.76 and 0.78; limits of agreement, -100 to 54.2 and -48.5 to 770 mL/min, respectively). Limits of agreement for the outer envelope tracing method were -238.5 to 64 mL/min. CONCLUSIONS AND CLINICAL RELEVANCE: Transcutaneous DDU is a reliable noninvasive technique for measuring blood flow in the femoral artery of pigs over a range of flow states. Tracing the inner envelope of the Doppler spectral dispersion pattern provided the best estimate of blood flow in this study.  相似文献   

Comparison of pharmacokinetic variables for two low-molecular-weight heparins after subcutaneous administration of a single dose to horses     

Schwarzwald CC  Feige K  Wunderli-Allenspach H  Braun U 《American journal of veterinary research》2002,63(6):868-873

OBJECTIVE: To determine pharmacokinetic variables and to evaluate the influence on clotting times after SC administration of single doses of dalteparin and enoxaparin to horses. ANIMALS: 5 healthy adult horses. PROCEDURES: The study was designed as a 4-period crossover study. Each horse received a single SC injection of dalteparin (50 and 100 anti-Xa U/kg) and enoxaparin (40 and 80 anti-Xa U/kg). Plasma anti-Xa activities and clotting times were measured, and pharmacokinetic variables were determined. Absolute and relative maximal prolongation of clotting times was calculated, and correlation between plasma anti-Xa activities and clotting times was determined. RESULTS: The SC administration of each of the doses of the 2 preparations was well tolerated. Time course of the anti-Xa activities could be described in a 1-compartment model. Comparison of low- and high-dose treatments revealed a disproportionate increase of the area under the plasma activity-time curve and prolongation of the terminal half-life, but the increase in maximum plasma activity was proportionate, and peak plasma concentrations corresponded with concentrations recommended in human medicine. There were only mild changes in activated partial thromboplastin time (aPTT), whereas the influence on thrombin time (TT) was greater, dose-dependent, and more variable. A weak-to-moderate correlation between aPTT and plasma anti-Xa activities and a moderate-to-strong correlation between TT and plasma anti-Xa activities were found. CONCLUSIONS AND CLINICAL RELEVANCE: Pharmacokinetic and anticoagulatory properties of low-molecular-weight heparins in horses are similar to those found in humans. Once-daily SC administration of dalteparin or enoxaparin may be useful as an anticoagulatory treatment in horses.  相似文献   

Estimation of left ventricular filling pressure by use of Doppler echocardiography in healthy anesthetized dogs subjected to acute volume loading     

Schober KE  Bonagura JD  Scansen BA  Stern JA  Ponzio NM 《American journal of veterinary research》2008,69(8):1034-1049

OBJECTIVE: To identify Doppler echocardiographic (DE) variables that correlate with left ventricular filling pressure (LVFP). ANIMALS: 7 healthy dogs (1 to 3 years old). PROCEDURES: Dogs were anesthetized and instrumented to measure left atrial pressure (LAP), left ventricular pressures, and cardiac output. Nine DE variables of LVFP derived from diastolic time intervals, transmitral and pulmonary venous flow, and tissue Doppler images were measured over a range of hemodynamic states induced by volume loading and right atrial pacing. Associations between simultaneous invasive measures of LVFP and DE measures of LVFP were determined by use of regression analysis. Receiver operating characteristic analysis was used to predict increases in mean LAP on the basis of DE variables. RESULTS: Mean LAP was correlated with several DE variables: the ratio between peak velocity during early diastolic transmitral flow and left ventricular isovolumic relaxation time (peak E:IVRT) during sinus rhythm and during right atrial pacing, IVRT, the ratio between late diastolic transmitral flow velocity and pulmonary venous flow duration, and the interval between onset of early diastolic mitral annulus motion and onset of early diastolic transmitral flow. Cutoff values of 2.20 and 2.17, for peak E:IVRT in dogs with sinus rhythm and atrial pacing predicted increases in mean LAP (> or = 15 mm Hg) with sensitivities of 90% and 100% and specificities of 92% and 100%, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Doppler echocardiography can be used to predict an increase in LVFP in healthy anesthetized dogs subjected to volume loading.  相似文献   

Über die Abhängigkeit der Tumor-Entwicklung vom Wirtsorganismus beim bakteriellen Pflanzenkrebs     

Uwe Karsten 《Genetic Resources and Crop Evolution》1965,13(1):737-761

Zusammenfassung Wachstumskurven vom bakteriellen Pflanzenkrebs (crown gall) an verschiedenen Wirtspflanzen (Pelargonium-Arten,Vicia faba, Bryophyllum daigremontianum) zeigen einen Verlauf, der dem anderer biologischer Wachstumsvorgänge außerordentlich ähnlich ist. In den Kurven verschiedener Sippen kommen genetisch bedingte Einflüsse des Wirtsorganismus auf die Tumorentwicklung zum Ausdruck. Sogar die Partnergewebe von Periklinalchimären können in dieser Beziehung unterschiedlich reagieren. Die Kurven schnell wachsender Tumoren nähern sich einer Grenzkurve, die als die Wachstumskurve voll alterierter Tumoren anzusehen ist. Bei Sippen mit langsam wachsenden Tumoren ist häufig die Anfangsphase gehemmt. Tumoranfälligkeit und Tumorwüchsigkeit sind in der Regel gleichsinnig beeinflußt.Mit dem Aufhören des Streckungswachstums entstehen weniger und kleinere Tumoren (Bryophyllum-Blätter,Vicia). Kinetin macht ältere Blätter vonBryophyllum nicht anfälliger. Die heranwachsenden Brutknospen hemmen die Entwicklung von Tumoren an den Blättern. Dekapitieren der Pflanzen fördert dagegen die Tumoren und überdeckt den Hemmungseffekt der Brutknospen. Diese und andere Versuche zeigen, daß pflanzliche Tumoren während der Induktionsphase und in geringerem Ausmaß auch noch später durch physiologische Mechanismen beeinflußbar sind.

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Summary Growth diagrams of crown gall tumors on different host plants (species ofPelargonium, Vicia faba, Bryophyllum daigremontianum) are very similar to those of other biological growth processes. Curves of different taxa reveal that development of tumors is influenced by the genetic constitution of host organism. Even partner-tissues of periclinal chimerae may react differently. Curves of rapidly growing tumors approach a limit which should be regarded as growth curve of fully alterated tumors. The initial phase of slowly growing tumors is often retarded. Sensitiveness to tumors and growth of tumors usually are influenced simultaneously.With the end of leaf growth fewer and smaller tumors arise (Bryophyllum-leaves,Vicia). Kinetin does not increase sensitivity to tumors in older leaves ofBryophyllum. Growing adventitious leaf-buds retard tumor development in leaves. Decapitating of plants favours tumors and covers the retarding effect of leaf buds. These and other experiments show that plant tumors may be influenced by physiological mechanisms during the inductive phase, and, though to a lesser extent, also later on.

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RADIOGRAPHIC AND ECHOCARDIOGRAPHIC ASSESSMENT OF LEFT ATRIAL SIZE IN 100 CATS WITH ACUTE LEFT‐SIDED CONGESTIVE HEART FAILURE     

Karsten E. Schober  Ellen Wetli  Wm Tod Drost 《Veterinary radiology & ultrasound》2014,55(4):359-367

The aims of this study were to evaluate left atrial size in cats with acute left‐sided congestive heart failure. We hypothesized that left atrial size as determined by thoracic radiography can be normal in cats with acute left‐sided congestive heart failure. One hundred cats with acute left‐sided congestive heart failure in which thoracic radiography and echocardiography were performed within 12 h were identified. Left atrial size was evaluated using right lateral and ventrodorsal radiographs. Measurements were compared to two‐dimensional echocardiographic variables of left atrial size and left ventricular size. On echocardiography, left atrial enlargement was observed in 96% cats (subjective assessment) whereas maximum left atrial dimension was increased (>15.7 mm) in 93% cats. On radiographs left atrial enlargement (subjective assessment) was found in 48% (lateral view), 53% (ventrodorsal view), and 64% (any view) of cats whereas left atrial enlargement was absent in 36% of cats in both views. Agreement between both methods of left atrial size estimation was poor (Cohen's kappa 0.17). Receiver operating characteristic curve analysis identified a maximum echocardiographic left atrial dimension of approximately 20 mm as the best compromise (Youden index) between sensitivity and specificity in the prediction of radiographic left atrial enlargement. Left atrial enlargement as assessed by thoracic radiography may be absent in a clinically relevant number of cats with congestive heart failure. Therefore, normal left atrial size on thoracic radiographs does not rule out presence of left‐sided congestive heart failure in cats with clinical signs of respiratory distress.  相似文献   

The Near Eastern origin of cat domestication     

Driscoll CA  Menotti-Raymond M  Roca AL  Hupe K  Johnson WE  Geffen E  Harley EH  Delibes M  Pontier D  Kitchener AC  Yamaguchi N  O'brien SJ  Macdonald DW 《Science (New York, N.Y.)》2007,317(5837):519-523

The world's domestic cats carry patterns of sequence variation in their genome that reflect a history of domestication and breed development. A genetic assessment of 979 domestic cats and their wild progenitors-Felis silvestris silvestris (European wildcat), F. s. lybica (Near Eastern wildcat), F. s. ornata (central Asian wildcat), F. s. cafra (southern African wildcat), and F. s. bieti (Chinese desert cat)-indicated that each wild group represents a distinctive subspecies of Felis silvestris. Further analysis revealed that cats were domesticated in the Near East, probably coincident with agricultural village development in the Fertile Crescent. Domestic cats derive from at least five founders from across this region, whose descendants were transported across the world by human assistance.  相似文献