QT instability, an indicator of augmented arrhythmogenesis, increases with the progression of myxomatous mitral valve disease in dogs.

OBJECTIVES: To investigate QT instability in dogs with myxomatous mitral valve disease (MMVD) and to determine if this is associated with arrhythmogenesis. ANIMALS: One hundred sixty-seven MMVD dogs that met the study criteria were included. METHODS: Echocardiographic and electrocardiographic data were gathered. Fifty consecutive QT intervals were recorded for each dog. Both heart rate-corrected and uncorrected QT intervals were used to calculate average QT (QTa), QT variance (QTv), total instability (TI), short-term instability (STI), and long-term instability (LTI). Sensitivity and specificity of QTa, QTv, TI, STI, and LTI in identifying arrhythmias and cardiac remodeling were calculated. Patient follow-ups were obtained for analyses of disease progression and survival. RESULTS: An increase related to progression was documented for all the studied indices. QTa and STI best identified dilated hearts and arrhythmias, respectively. Dogs with QTa >272 ms and STI >8 ms were 15% more likely to develop ventricular arrhythmias (likelihood ratios of 2.31 [P = 0.0008] and 2.09 [P = 0.0049], respectively). A QTa >258 ms discriminated American College of Veterinary Internal Medicine stage B1 from stages B2/C disease with a sensitivity of 63% and specificity of 61%. Dogs in American College of Veterinary Internal Medicine stage C of MMVD have higher STI and 3.34 times increased risk of developing arrhythmias when values more than 8 ms are reached. All indices except LTI and QTv showed prognostic value, with increases relating to all-cause mortality. CONCLUSION: Analyses of QT intervals demonstrated changes in STI, LTI, and TI. Increased QT prolongation and instability are significantly related to mortality and may be useful in determining prognosis of MMVD patients.

[The supply of wild ruminants with major and trace elements. 2. The manganese content of winter grazing and the manganese status of red deer, fallow deer, roes and mouflons]. / Die Mengen- und Spurenelementversorgung der Wildwiederkäuer. 2. Mitteilung: Der Mangangehalt der Winteräsung und der Manganstatus des Rot-, Dam-, Reh- und Muffelwildes.

The winter grazing of wild ruminants on mantles of slate waste in the Harz mountains and in Gera county were richest in Mn whereas those on mantles of granite waste in the Erzgebirge were poorest. The flora of the shell-limestone, keuper and loess areas contains much less Mn than that of those acid habitats. The Mn-requirement of the wild ruminants grazing in the forests is met however, since bilberry plants (2,080 mg/kg), spruce twigs (984 mg/kg), spruce bark (827 mg/kg), oak twigs (791 mg/kg) and heather (754 mg/kg dry matter) in addition to many other plant species store extremely high amounts of Mn. Solely sallow twigs were poor in Mn (28 mg/kg). Based on 601 samples examined, the Mn supply of wild ruminants is extensively described. The rumen content reflected the plentiful Mn-supply of the wild ruminants living in forests (greater than 400 mg/kg) and the far worse one of field roes, particularly in Mn-deficiency areas for domesticated ruminants (mantle of shell-limestone waste 37 mg Mn/kg dry matter of rumen content). The indicator organs of the Mn-status (liver, covering hair, kidneys) verify the statements made concerning red deer, fallow deer and mouflons, of which a total of 170 head from 14 biotopes were examined. An Mn-deficit of field roes in Mn-deficiency habitats in winter cannot completely be excluded. Mouflons have not yet been able to adapt themselves to the excessive Mn-supply of the acid forest habitats in Central Europe. They stored significantly higher amounts of Mn in liver, covering hair, kidneys, cerebrum and ribs than the other wild ruminants and sheep and cattle. The normal Mn-content of the liver and the cerebrum of red deer, fallow deer and roes corresponds to that of sheep and cattle. Roes and fallow deer have winter covering hair poor in Mn (less than 4.0 mg/kg) in comparison to sheep and cattle.

Epithelial nephrogenesis.

The metanephric, or definitive, kidney forms as a result of inductive processes between tissues of two distinct embryologic origins, the metanephric mesenchymal blastema and the ureteric bud. After inductive signalling between these primordial tissues, mesenchymal cells aggregate next to the branching ureteric bud tip, convert to epithelial cells and differentiate into the diverse cell populations of the nephron. The ureteric bud enters branching morphogenesis and gives rise to the collecting duct system. Nephrogenesis has become a target system by which to study developmental processes including embryonic inductive interactions, mesenchyme-to-epithelium conversion, cell lineage pathways, epithelial cell polarization, branching morphogenesis and spatio-temporal expression of transcription factors. This review summarizes data on cellular and extracellular events during epithelial metanephrogenesis.