Entwicklung eines In-vitro-Resistenztests für den Erreger des Schwarzrostes (Puccinia graminis ssp. graminicola) an Deutschem Weidelgras (Lolium perenne L.) und molekulare Charakterisierung eines dominanten Resistenzgens

Schwarzrost, verursacht durch Puccinia graminis ssp. graminicola, ist zunehmend ein Problem in der Grassamenproduktion Deutschlands. Höhere Sommertemperaturen und mildere Winter haben die Ausbreitung und Befallsstärke von Schwarzrost in Vermehrungsbeständen in den letzten Jahren stark ansteigen lassen. Schwarzrostinfektionen, die zu hohen Ertragsausfällen und zu verminderter Qualität des Erntegutes führen, sind auf Grund fehlender resistenter Sorten nur durch kostenintensive prophylaktische Fungizidmaßnahmen zu verhindern. Der damit sinkende Deckungsbeitrag der Grassamenproduktion veranlasst viele Landwirte, auf den Anbau anderer Kulturarten auszuweichen. Auf Grund der Witterungsabhängigkeit der Schwarzrostepidemien und damit einhergehender saisonaler Unterschiede im Infektionsdruck ist es nicht in jedem Jahr möglich, auf Schwarzrostresistenz im Feld zu bonitieren. Daher sollte eine effiziente Möglichkeit der witterungsunabhängigen Selektion zur Entwicklung resistenter Sorten gefunden werden. Ein Blattsegmenttest für Schwarzrostresistenz bei Lolium perenne wurde entwickelt, der einfach in der Anwendung ist und die Möglichkeit einer sicheren und kostengünstigen Schwarzrostbonitur auch außerhalb der Saison bietet. Seine Ergebnisse waren in hohem Maße reproduzierbar und zeigten trotz erschwerter Datenerfassung im Feldversuch erste Hinweise auf eine gute Übereinstimmung mit den Feldbonituren. Geprüft wurden 340 Prüfglieder einer im Blattsegmenttest für Schwarzrostresistenz 1:1 aufspaltenden Familie über zwei Jahre an drei Orten mit jeweils zwei Wiederholungen. Auf Grundlage des Tests konnte eine monogene, dominant ausgeprägte Vererbung der Resistenz für Schwarzrost innerhalb der Familie nachgewiesen werden. Dem zugrunde liegenden Resistenzgen wurde die Bezeichnung LpPg1 gegeben. Die breite Wirksamkeit der LpPg1-vermittelten Resistenz gegenüber unterschiedlichen Schwarzrost-Inokuli ist ein erster Hinweis auf eine gute Beständigkeit und damit lange Nutzungsdauer der Resistenz. Durch molekulare Analysen mit 82 Resistenzgenanalogern (RGA) und 162 Simple Sequenz Repeats (SSR) konnten drei mit LpPg1 gekoppelte SSR-Marker detektiert werden, darunter zwei flankierende Marker, die in Abständen von 2,6 und 6,7 cM zum Resistenzgen kartieren. Diese flankierenden Marker zeigen gemeinsam weniger als 1 % Rekombination zum Resistenzgen und bieten so die Möglichkeit einer effizienten Marker-gestützten-Selektion innerhalb von Rückkreuzungs- oder Pyramidisierungsprogrammen. Zudem weisen die mit dem Resistenzgen gekoppelten Marker auf eine Lage des Resistenzgens auf LG 4 nach Hirta et al. 2006 hin.Stem rust caused by Puccinia graminis ssp. graminicola is a dramatic problem for grass seed production in many areas of the world. Higher temperatures in summer and mild winters as a consequence of the climatic change lead to an increased occurrence of stem rust in the field over the last years. Infections lead to yield reduction and reduced seed quality. In Germany, resistant varieties are failing and treatments with fungicides are difficult and expensive. The reduced benefit of grass seed production makes the cultivation of other crops more and more attractive. The amount of stem rust infection depends on the climatic conditions in spring and summer, therefore an evaluation of stem rust in field trials is not always possible. A detached-leaf test for resistance of Lolium perenne to stem rust has been developed, which is easy to use and gives the opportunity of a stem-rust evaluation independent of environment and climatic conditions. Its results indicate a high robustness of the test and show, despite difficult evaluation in the field trials, good correlations to the field results. Field trials with 340 single plants of a population showing 1:1 segregation in the leaf segment test for stem rust resistance were carried out over two years on three locations with two replications. Using the leaf segment test, the monogenic, dominantly inherited resistance to stem rust in Lolium perenne LpPg1 was found and characterised. Correlation coefficients obtained for infestation scores in independent tests and with plants of varying age indicated satisfactory robustness of the test procedure and stage-independency of the resistance. Reaction to different inoculi of the pathogen indicated a broad effectiveness of the resistance. Analysis with 82 genomic resistance gene analogs (RGA) and 162 simple sequence repeat (SSR) markers identified three markers which are linked to the resistance gene LpPg1. Two flanking markers were mapped 2.6 and 6.7 cM to the resistance gene and may be used for marker assisted selection (MAS) in backcrossing and pyramiding programs. Besides that, the correlated markers give a first indication for the position of LpPg1 on linkage group 4 (Hirta et al. 2006)

Solitary intraventricular tumors in dogs and cats treated with radiotherapy alone or combined with ventriculoperitoneal shunts: A retrospective descriptive case series

Background: Intraventricular tumors are rare, optimal treatment is not defined. Symptomatic patients often exhibit life-threatening hydrocephalus. With several months time-to-effect after radiotherapy (RT), increased intracranial pressure is concerning. This increase in pressure can be overcome by ventriculoperitoneal shunting (VPS). Objectives: Retrospective evaluation of outcome and complications in dogs and cats with intracranial tumors treated with either RT or VPS/RT. Animals: Twelve client-owned cats and dogs. Methods: Dogs and cats with symptomatic intraventricular tumors treated with definitive-intent RT or VPS/RT were included in a retrospective, descriptive case series. Complications, tumor volume evolution, time-to-progression, and survival time were determined. Results: Twelve animals were included: 1 cat and 5 dogs treated with single-modality RT and 4 cats and 2 dogs treated with VPS/RT. Neurological worsening seen in 4/6 animals during single-modality RT and 2/6 died during RT (suspected brain herniation). All dogs with VPS normalized clinically by the end of RT or earlier. Complications occurred in 4/6 animals, all but 1 were successfully managed surgically. Imaging follow-up in 8 animals surviving RT showed a marked decrease in tumor volume. Median survival time was 162 days (95% confidence interval [CI]: 16; infinity) for animals treated with RT and 1103 days (95%CI: 752; infinity) for animals treated with VPS/RT. Median time-to-progression was 71 days (95%CI: 7; infinity) and 895 days (95%CI: 704; infinity) for each group, respectively. Two dogs died because of intraventricular metastasis 427 and 461 days after single-modality RT. Conclusions and clinical importance: Ventriculoperitoneal shunting led to rapid normalization of neurological signs and RT had a measurable effect on tumor volume. Combination of VPS/RT seems to be beneficial

Challenges in diagnosing a peripheral nerve sheath tumor of the ulnar nerve in a dog – a case report

In this case report we present the rare case of a distally located peripheral nerve sheath tumor (PNST) of the left ulnar nerve in a two-year-old female Rottweiler dog. We discuss the clinical and diagnostic findings and the challenges of the diagnosis. The dog was successfully treated with a limb sparing partial neurectomy. After surgery, the dog did not show any pain or lameness on long term follow-up

Diagnosis of post-attenuation neurological signs syndrome in a cat with refractory status epilepticus and clinical response to therapeutic plasma exchange

Case summary An 8-year-old female spayed British Shorthair cat that underwent surgical portosystemic shunt (PSS) attenuation developed progressive neurological signs 7 days postoperatively. Neurological signs progressed, despite medical management, and seizure activity became rapidly refractory to anticonvulsants. The diagnosis of post-attenuation neurological signs (PANS) was made based on the timing of the occurrence of clinical signs following surgery, absence of hyperammonaemia and suggestive MRI findings of the brain. The cat developed status epilepticus that required treatment with general anaesthesia and mechanical ventilation, from which the cat could not be effectively weaned without the recurrence of seizures. Therapeutic plasma exchange (TPE) was performed as a rescue therapy for PANS and associated refractory status epilepticus. A total of two plasma volumes were processed during one single TPE session. The seizure activity resolved immediately after the TPE session, the cat showed progressive improvement of neurological signs and remained stable thereafter. No significant complications associated with the TPE were observed. The cat was discharged 11 days after admission and was fully recovered. Relevance and novel information This is an unusual report of PANS diagnosed in a cat based on clinical and MRI findings. The cat developed refractory status epilepticus and had a positive outcome following TPE as rescue therapy. The MRI findings in this report could be useful for the diagnosis of PANS in cats. We speculate that TPE could be taken into consideration as a possible therapeutic intervention in PANS syndrome

Safety and efficacy of intravenously administered tedisamil for rapid conversion of recent-onset atrial fibrillation or atrial flutter

AbstractObjectivesThe goal of the present study was to assess the efficacy and safety of intravenous tedisamil, a new antiarrhythmic compound, for conversion of recent-onset atrial fibrillation (AF) or atrial flutter (AFL) to normal sinus rhythm (NSR).BackgroundTedisamil is a novel antiarrhythmic drug with predominantly class III activity. Its efficacy and safety for conversion of recent onset AF or AFL to NSR is not known.MethodsThis was a multicenter, double-blind, randomized, placebo-controlled, sequential ascending dose-group trial. A total of 201 patients with symptomatic AF or AFL of 3 to 48 h duration were enrolled in a two-stage study. During stage 1, patients were randomized to receive tedisamil at 0.4 mg/kg body weight or matching placebo; during stage 2, patients received tedisamil at 0.6 mg/kg body weight or matching placebo. Treatments were given as single intravenous infusions. The primary study end point consisted of the percentage of patients converting to NSR for at least 60 s within 2.5 h.ResultsOf 175 patients representing the intention-to-treat sample, conversion to NSR was observed in 41% (25/61) of the tedisamil 0.4 mg/kg group, 51% (27 of 53) of the tedisamil 0.6 mg/kg group, and 7% (4/59) of the placebo group (p < 0.001 for both tedisamil groups vs. placebo). Average time to conversion was 35 min in patients receiving tedisamil. There were two instances of self-terminating ventricular tachycardia: one episode of torsade de pointes and one of monomorphic ventricular tachycardia, both in patients receiving 0.6 mg/kg tedisamil.ConclusionsTedisamil at dosages of 0.4 and 0.6 mg/kg was superior to placebo in converting AF or AFL. Tedisamil has a rapid onset of action leading to conversion within 30 to 40 min in the majority of responders

Single-Voxel Proton Magnetic Resonance Spectroscopy of the Thalamus in Idiopathic Epileptic Dogs and in Healthy Control Dogs

The role of magnetic resonance spectroscopy (MRS) in the investigation of brain metabolites in epileptic syndromes in dogs has not been explored systematically to date. The aim of this study was to investigate metabolites in the thalamus in dogs affected by idiopathic epilepsy (IE) with and without antiepileptic drug treatment (AEDT) and to compare them to unaffected controls. Our hypothesis is that similar to humans with generalized epilepsy and loss of consciousness, N-acetyl aspartate (NAA) would be reduced, and glutamate-glutamine (Glx) would be increased in treated and untreated IE in comparison with the control group. In this prospective case-control study, Border Collie (BC) and Greater Swiss Mountain dog (GSMD) were divided into three groups: (1) healthy controls, IE with generalized tonic-clonic seizures with (2) and without (3) AEDT. A total of 41 BC and GSMD were included using 3 Tesla single-voxel proton MRS of the thalamus (PRESS localization, shortest TE, TR = 2000 ms, NSA = 240). After exclusion of 11 dogs, 30 dogs (18 IE and 12 healthy controls) remained available for analysis. Metabolite concentrations were estimated with LCModel using creatine as reference and compared using Kruskal-Wallis and Wilcoxon rank-sum tests. The Kruskal-Wallis test revealed significant differences in the NAA-to-creatine (p = 0.04) and Glx-to-creatine (p = 0.03) ratios between the three groups. The Wilcoxon rank-sum test further showed significant reduction in the NAA/creatine ratio in idiopathic epileptic dogs under AEDT compared to epileptic dogs without AEDT (p = 0.03) and compared to healthy controls (p = 0.03). In opposite to humans, Glx/creatine ratio was significantly reduced in dogs with IE under AEDT compared to epileptic dogs without AEDT (p = 0.03) and controls (p = 0.02). IE without AEDT and healthy controls did not show significant difference, neither in NAA/creatine (p = 0.60), nor in Glx-to-creatine (p = 0.55) ratio. In conclusion, MRS showed changes in dogs with IE and generalized seizures under AEDT, but not in those without AEDT. Based upon these results, MRS can be considered a useful advanced imaging technique for the evaluation of dogs with IE in the clinical and research settings

A shortened whole brain radiation therapy protocol for meningoencephalitis of unknown origin in dogs

IntroductionA variety of treatment options have been described for canine meningoencephalitis of unknown origin (MUO). Few studies focused on radiation therapy as a second line immunomodulating treatment, implicating its effective use. However, a standard radiation therapy protocol is lacking, and further research will help to evaluate the effect of different dose regimens.MethodsTen dogs diagnosed with MUO based on MRI and CSF findings were prospectively enrolled. The dogs were treated with a shortened whole brain radiation therapy protocol (5 × 4 Gy) in combination with prednisolone. Neurologic changes were quantified using an established scoring scheme. Follow-up MRI and CSF examination was scheduled three months after radiation therapy. Overall survival and time to progression were calculated. Histopathology of the brain was performed in case of death.ResultsSeven dogs were diagnosed de novo and three had a history of relapsing MUO. Neurological status improved in all 10 dogs during radiation therapy, with 4/10 returning to normal shortly after radiation therapy. Three dogs died within the first three months after radiation therapy. At follow-up MRI lesions completely resolved in two dogs, partially resolved in five dogs, and progressed in one dog. After follow-up MRI, dogs were further treated with prednisolone monotherapy (two dogs) and additional immunosuppressant drugs (five dogs). Overall, four dogs showed disease progression, with a mean time to progression of 691 days (95%CI: 396–987) and mean overall survival for all dogs was 723 days (95%CI: 436–1011) (both medians not reached). Histopathology confirmed MUO in three dogs but was suggestive for oligodendroglioma in one dog. Radiation induced side effects were not seen.ConclusionShortened whole-brain radiation therapy could be an additional treatment option for MUO in conjunction to prednisolone, specifically for cases that require rapid relief of symptoms and with relapsing history

Treatment of intracranial neoplasia in dogs using higher doses: A randomized controlled trial comparing a boosted to a conventional radiation protocol

Background: Local progression of intracranial tumors can be the consequence of insufficient radiation dose delivered. Dose increases in the brain must be made carefully so as not to risk debilitating adverse effects such as radiation necrosis. Hypothesis: A new protocol with 10 × 4 Gy + 11% physical dose increase limited to the macroscopic tumor volume results in a clinically better outcome compared to a 10 × 4 Gy protocol. Animals: Fifty-seven client-owned dogs with primary intracranial neoplasia. Methods: Randomized controlled trial. Twenty-eight dogs were assigned to the control protocol (10 × 4 Gy) and 29 to the simultaneous integrated boost (SIB) protocol with 4.45 Gy dose increase. Treatment groups were compared for outcome and signs of toxicity. Results: Mild, transient acute or early-delayed adverse radiation effects were observed in 5 dogs. Severe late adverse effects were not seen. Between the protocols, no significant differences were found for outcome (intention-to-treat analysis): overall time to progression (TTP) was 708 days (95% confidence interval (95% CI) [545,872]), in the control group it was 828 days (95% CI [401,1256]), and in the SIB group 627 days (95% CI [282,973]; P = .07). Median overall survival (OS) was 684 days (95% CI [516,853]), in the control group it was 724 days (95% CI [623,826]), and in the SIB group 557 days (95% CI [95,1020]; P = .47). None of the tested variables was prognostic in terms of outcome. Conclusion and clinical importance: The dose escalation used with an 11% physical dose increase did not result in better outcome

Evaluating the use of cytosine arabinoside for treatment for recurrent canine steroid-responsive meningitis-arteritis

BackgroundRelapses in steroid-responsive meningitis-arteritis (SRMA) are frequently observed but specific treatment protocols to address this problem are sparsely reported. Standard treatment includes prolonged administration of glucocorticoids as monotherapy or in combination with immunosuppressive drugs. The aim of this study was to assess the safety and efficacy of cytosine arabinoside (CA) in combination with glucocorticoids for treatment of SRMA relapses in 12 dogs on a retrospective basis.MethodsDogs with recurrent episodes of SRMA and treated with a combination of CA and prednisolone were included. Information about clinical course, treatment response and adverse events was collected from medical records. Ethical approval was not required for this study.ResultsTen dogs (10/12) responded well to the treatment with clinical signs being completely controlled. One dog is in clinical remission, but still under treatment. One dog (8%) showed further relapse. Mean treatment period was 51 weeks. Adverse events of variable severity (grade 1–4/5) were documented in all dogs during treatment according to the veterinary cooperative oncology group grading. Three dogs developed severe adverse events. Laboratory findings showed marked changes up to grade 4. Diarrhoea and anaemia were the most often observed adverse events (6), followed by dermatitis (4), alopecia (3) and pneumonia (3). Including blood chemistry changes (13), 50 adverse events were found in total.ConclusionTreatment with CA and glucocorticoids resulted in clinical remission in 10/12 dogs, but a high incidence of adverse events occurred requiring additional measures. All adverse events could be managed successfully in all cases.</jats:sec