Brainstem auditory-evoked potential assessment of auditory function and congenital deafness in llamas (Lama glama) and alpacas (L. pacos)     

Gauly M  Vaughan J  Hogreve SK  Erhardt G 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2005,19(5):756-760

Auditory function of llamas and alpacas was assessed objectively by means of brainstem auditory-evoked response audiometry (BAER) to establish the normal hearing range and to test the hypothesis of a correlation between blue eyes, white coat, and deafness. Sixty-three camelids were available for the study. Thirteen animals had blue irides; 1 animal had 1 blue and 1 pigmented iris. Wave latencies, amplitudes, and interpeak latencies were measured under general anesthetic. Click stimuli (dB [HL]) were delivered by an insert earphone. Four to five positive peaks could be detected; waves I, II, and V were reproducible; wave II appeared infrequently; and wave IV generally merged with wave V to form a complex. Peak latencies decreased and peak amplitudes increased as stimulus intensity increased. A hearing threshold level of 10-20 dB (HL) was proposed as the normal range in llamas and alpacas. None of the animals with pigmentation of coat and iris showed any degree of hearing impairment. Seven of the 10 blue-eyed, pure-white animals were bilaterally deaf and one of them was unilaterally deaf. However, 2 blue-eyed, white animals exhibited normal hearing ability. Three blue-eyed animals with pigmented coat did not show any hearing impairment. All white animals with normal iris pigmentation had normal auditory function; so did the 1 animal with 1 normal and 1 blue iris. The high frequency (78%) of bilaterally deaf animals with pure white coat and blue iris pigmentation supports the hypothesis of a correlation between pigmentation anomalies and congenital deafness in llamas and alpacas.  相似文献   

Modified vaccinia virus Ankara as a vaccine against feline coronavirus: immunogenicity and efficacy     

Hebben M  Duquesne V  Cronier J  Rossi B  Aubert A 《Journal of Feline Medicine and Surgery》2004,6(2):111-118

Feline infectious peritonitis virus (FIPV) is a coronavirus that induces a fatal systemic disease mediated by an inappropriate immune response. Most previous vaccination attempts against FIPV were unsuccessful because IgG antibodies against the surface protein enhance the infection. However, two studies have shown that poxvirus vectors (vaccinia WR and canarypox) expressing only the FIPV membrane (M) protein can elicit a partially protective immunity which is supposed to be cell-mediated (Virology 181 (1991) 327; International patent WO 97/20054 (1997)). In our study, we report the construction of another poxvirus, the modified vaccinia virus Ankara (MVA), as an expression vector for the FIPV M protein. In this vector, the M gene has been inserted downstream a strong early/late promoter, whereas the two previously described poxviruses expressed the M protein during their early stage only. The immunogenicity of the recombinant MVA-M was evaluated in the murine model which revealed an effect of the vector on the Th1/Th2 balance. The vaccine was then tested in cats to evaluate its efficacy in an FIPV 79-1146 challenge. Vaccinated kittens developed FIPV-specific antibodies after immunization, however, none of them was protected against FIPV. Our results suggest a crucial role for the type of poxviral promoter that must be used to induce an effective immune response against FIPV.  相似文献   

Erzeugung transgener steriler Zitterpappeln zur Verhinderung eines vertikalen Gentransfers in forstliche Ökosysteme     

Matthias Fladung  Hans Hönicka 《Gesunde Pflanzen》2004,56(7-8):195-200

Zusammenfassung Die Anwendung gentechnischer Methoden bei langlebigen Forstpflanzen ist für eine schnelle und effiziente Entwicklung verbesserter Linien besonders attraktiv. Da jedoch in heimischen Waldökosystemen eine freie Kreuzbarkeit zwischen gentechnisch veränderten und nicht gentechnisch veränderten Bäumen angenommen werden muss, ist eine Introgression der gentechnisch übertragenen Gene (Transgene) in den Genpool der entsprechenden Arten zu erwarten (vertikaler Genfluss). Eine mögliche Strategie zur Verhinderung dieses vertikalen Gentransfers ist die Induktion einer männlichen und/oder weiblichen Sterilität. Sicherheitsstudien bei transgenen Forstpflanzen leiden jedoch unter der Problematik von langen Generationszeiten bei Bäumen. Beispielsweise benötigen Pappeln sieben bis zehn Jahre für den Eintritt in die generative Phase. Daher ist die Förderung der Blühinduktion bei transgenen Pappeln im Rahmen der Untersuchungen zur Sterilität sehr wichtig. Neben einem physiologischen Ansatz wurden für die Erzeugung frühblühender Pappellinien in einem gentechnischen Ansatz die Gene Leafy (LFY) und MADS4 (Frühblühgene) getestet. Frühe Blütenbildung ist bei sechs bis acht Wochen alten Leafy-transgenen Linien beobachtet worden. Für 35S::MADS4-transgene Pflanzen konnte bisher noch keine Blütenbildung festgestellt werden. Weibliche und männliche Pappelklone wurden sowohl mit den Frühblühgenen als auch mit Sterilitätskonstrukten transformiert. Damit ist es möglich, in einem gegebenen Zeitrahmen von zwei bis drei Jahren die von transgenen Pappellinien gebildeten Blüten hinsichtlich Fertilität/Sterilität zu untersuchen.  相似文献   

MEASUREMENT OF TUMOR HYPOXIA IN SPONTANEOUS CANINE SARCOMAS     

Matthias Bruehlmeier  Barbara Kaser-Hotz  Roger Achermann  Carla Rohrer Bley  Melanie Wergin  Pius A. Schubiger  Simon M. Ametamey 《Veterinary radiology & ultrasound》2005,46(4):348-354

We used positron emission tomography (PET) with [18F]fluoromisonidazole ([18F]FMISO) to study tumor hypoxia in six dogs with spontaneous sarcomas. The tumors were regarded as hypoxic if [18F]FMISO uptake exceeded normal tissue radioactivity by 40% (tumor/muscle ratio > 1.4) or if kinetic analysis indicated a positive [18F]FMISO tissue influx rate (Ki > 0) by a Patlak plot. Using these criteria, we found hypoxia in a fibrosarcoma grade II, an undifferentiated sarcoma, and an ostoeosarcoma, but not in a fibrosarcoma grade I, another osteosarcoma, and a myxosarcoma. In three animals, the tumor oxygen partial pressure (pO2) was also measured invasively using Eppendorf needle electrodes. In these cases, the Eppendorf measurements were confirmed by the [18F]FMISO PET results. In addition, [15O]H2O PET was performed in four dogs in order to assess tumor perfusion. Comparisons of the [18F]FMISO with [15O]H2O PET images in two cases showed that tumor hypoxia occurred in the tumor center with low perfusion, whereas perfusion was heterogeneous in a nonhypoxic tumor.  相似文献   

Driving forces of landscape change - current and new directions     

Matthias Bürgi  Anna M. Hersperger  Nina Schneeberger 《Landscape Ecology》2005,19(8):857-868

The concept of driving forces is gaining increasing attention in landscape-change research. We summarize the state of the art of this field and present new conceptual and methodological directions for the study of driving forces of landscape changes. These new directions address four major challenges faced by landscape-change studies, i.e., studying processes and not merely spatial patterns, extrapolating results in space and time, linking data of different qualities, and considering culture as a driver of landscape change. The proposed research directions include: studying landscape change across borders and transects, focusing on persistence as well as change, investigating rates of change, considering attractors of landscape change, targeting correlation and causality, and searching for precursors of landscape change. Based on established knowledge and the new approaches we outline a standard procedure to study driving forces of landscape change. We anticipate that our analytical and systematic approach increases the relevance of studies of landscape change for science as well as for the solution of real world problems.  相似文献   

Genetic heterogeneity of bovine viral diarrhoea virus (BVDV) isolates from Turkey: identification of a new subgroup in BVDV-1   总被引：1，自引：0，他引：1  

Kadir Y  Christine F  Barbara BW  Zeki Y  Feray A  Aykut O  Ibrahim B  Sibilina Cedillo R  Heinz-Jürgen T  Matthias K 《Veterinary microbiology》2008,130(3-4):258-267

Genetic heterogeneity of Turkish ruminant pestiviruses was investigated by phylogenetic analysis of complete N(pro) encoding nucleotide sequences. A total of 30 virus isolates obtained from 15 provinces around the country between 1997 and 2005 were included in the phylogenetic analysis. Virus isolates mostly originated from cattle with one isolate from sheep. The bovine isolates all belonged to BVDV-1, the sheep isolate to BVDV-2. Fifteen isolates formed a new subgroup within BVDV-1, tentatively named BVDV-1l. The remaining bovine isolates were typed as BVDV-1a (n=4), BVDV-1b (n=4), BVDV-1d (n=3), BVDV-1f (n=2) and BVDV-1h (n=1). The isolates allocated to BVDV-1l originated from various geographical regions in different years. There was no correlation between genetic grouping and locations where isolates were obtained. Viruses originating from one farm in most cases belonged to the same subgroup (n=5). This study indicates that the newly detected subgroup BVDV-1l is predominant and widespread in Turkey. Moreover, an ovine virus isolate was identified as the first member of BVDV-2 reported in Turkey. A serological survey using samples from western Turkey indicated that BVDV-2 is also present in cattle.  相似文献   

Cardiac‐gated,phase contrast magnetic resonance angiography is a reliable and reproducible technique for quantifying blood flow in canine major cranial abdominal vessels          下载免费PDF全文

Francesca Del Chicca  Andrea Schwarz  Paula Grest  Florian Willmitzer  Matthias Dennler  Patrick R. Kircher 《Veterinary radiology & ultrasound》2018,59(4):423-431

Blood flow changes in cranial abdominal vessels are important contributing factors for canine hepatic disease. This prospective, experimental, pilot study aimed to evaluate cardiac‐gated, phase contrast magnetic resonance angiography (PCMRA) as a method for characterizing blood flow in canine major cranial abdominal vessels. Eleven, healthy, adult beagle dogs were sampled. Cardiac‐gated, phase contrast magnetic resonance angiography of the cranial abdomen was performed in each dog and blood flow was independently measured in each of the major cranial abdominal vessels by three observers, with two observers recording blood flow values once and one observer recording blood flow values three times. Each dog then underwent ultrasonographic examination of the liver with fine needle aspirations and biopsies submitted to cytologic and histologic examination. The mean absolute stroke volume and velocity were respectively 9.6 ± 1.9 ml and –11.1 ± 1.1 cm/s for the cranial abdominal aorta, 2.1 ± 0.6 ml and –6.6 ± 1.9 cm/s for the celiac artery, and 2.3 ± 1.0 ml and –7.9 ± 3.1 cm/s for the cranial mesenteric artery. The mean absolute stroke volume and velocity were respectively 6.7 ± 1.3 ml and 3.9 ± 0.9 cm/s for the caudal vena cava and 2.6 ± 0.9 ml and 3.2 ± 1.2 cm/s for the portal vein. Intraobserver reliability was excellent (intraclass correlation coefficient > 0.9). Interobserver reproducibility was also excellent (intraclass correlation coefficient 0.89–0.99). Results of liver ultrasonography, cytology, and histopathology were unremarkable. Findings indicated that cardiac‐gated, phase contrast magnetic resonance angiography is a feasible technique for quantifying blood blow in canine major cranial abdominal vessels. Blood flow values from this sample of healthy beagles can be used as background for future studies on canine hepatic disease.  相似文献   

Detection of vascular endothelial growth factor (VEGF) and VEGF receptors Flt-1 and KDR in canine mastocytoma cells     

Rebuzzi L  Willmann M  Sonneck K  Gleixner KV  Florian S  Kondo R  Mayerhofer M  Vales A  Gruze A  Pickl WF  Thalhammer JG  Valent P 《Veterinary immunology and immunopathology》2007,115(3-4):320-333

Vascular endothelial growth factor (VEGF) is a major regulator of angiogenesis and a potential autocrine growth factor for neoplastic cells in various malignancies. In the present study, we have investigated expression of VEGF and VEGF receptors in canine mastocytomas and the canine mastocytoma cell line C2. As assessed by immunostaining of tissue sections and cytospin slides, primary neoplastic mast cells (MC) and C2 cells were found to express the VEGF protein. In Northern blot and RT-PCR experiments, C2 cells expressed VEGF mRNA in a constitutive manner. VEGF mRNA expression in C2 cells was counteracted by LY294002 and rapamycin, suggesting involvement of the PI3-kinase/mTOR pathway. Moreover, C2 cells were found to express VEGF receptor-1 (Flt-1) and VEGF receptor-2 (KDR). However, recombinant VEGF failed to promote (3)H-thymidine uptake in C2 cells, and a neutralizing anti-VEGF antibody (bevacizumab) failed to downregulate spontaneous proliferation in these cells. In addition, rapamycin decreased the expression of VEGF in C2 cells at the mRNA and protein level without suppressing their proliferation. Together, canine mastocytoma cells express VEGF as well as VEGF receptors. However, despite co-expression of VEGF and its receptors, VEGF is not utilized as an autocrine growth regulator by canine mastocytoma cells.  相似文献   

Effect of Ski Mountaineering Track on Foot Sole Loading Pattern     

Matthias Haselbacher  Katharina Mader  Maximiliane Werner  Michael Nogler 《The Forestry Chronicle》2014,25(3):335-339

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Superconductivity of alpha-uranium and the role of 5f electrons     

Geballe TH  Matthias BT  Andres K  Fisher ES  Smith TF  Zachariasen WH 《Science (New York, N.Y.)》1966,152(3723):755-757

A much sharper and lower superconducting transition has been found for alpha-uranium than any reported previously. A model that explains the unusual volume dependence of alpha-uranium below 43 degrees K and the unusual pressure dependence of its superconducting transition temperature is presented.  相似文献