Rapid ventricular pacing in dogs results in a low output cardiomyopathic state which is similar to idiopathic dilated cardiomyopathy in man. However, the pathophysiological mechanisms which cause this failure following pacing are unknown. Five dogs underwent rapid ventricular pacing. Hearts were stimulated at 245 beats per min (bpm) for four weeks and then reduced to 190 bpm to stabilize the failure. Six unoperated dogs were used as controls. This paper compares the two-dimensional gel electrophoresis (2-DE) protein patterns of left ventricular samples from the paced myocardium with the control dogs. Changes in protein expression were analyzed qualitatively and semi-quantitatively. In the paced dog samples 69 protein spots were significantly altered of which 42 were decreased and 27 were elevated. One qualitative change was observed: elongation factor Tu was present only the control hearts. Of these proteins, 20 have been identified by a combination of N-terminal protein microsequencing, peptide mass profiling by mass spectrometry, amino acid compositional analysis, and by comparison with databases of canine and human ventricular proteins. Ten of these are associated with mitochondria and energy production, including: pyruvate dehydrogenase E1 component, isocitrate dehydrogenase subunit alpha, HSP60 and HSP70, creatine kinase M and fatty acid binding protein. The cytoskeletal protein desmin was detected in reduced quantities and a spot corresponding to a fragment of desmin was increased. These results indicate that the development of heart failure in the paced dog involves alterations in mitochondrial energy production, the cytoskeleton and calcium activation.
Canine rapid ventricular pacing produces a low output cardiomyopathic state which is similar to dilated cardiomyopathy. In this study dogs were paced at 245 beats per minute (bpm) for 3—4 weeks until signs of heart failure were apparent. Unpaced dogs were used as controls. A previous study identified myocardial protein changes in the pH region 4—7 following ventricular pacing by using two‐dimensional electrophoresis (2‐DE) (Heinke et al., Electrophoresis 1998 19, 2021—2030). Many of these proteins were associated with mitochondria, energy metabolism within the cardiomyocyte, the cytoskeleton and calcium cycling. The present study aimed to examine the proteins migrating in the more basic region of the 2‐DE pattern using immobilised pH gradient 3—10 strips to separate myocardial proteins. The expression of 31 proteins was altered in the paced myocardium: 21 were decreased and 10 increased. Following the identification of 23 of these spots by either amino acid compositional analysis or peptide mass fingerprinting or a combination of both, we confirm that many of the proteins whose expression is altered following ventricular pacing are associated with the mitochondria and energy production within the cardiomyocyte, including creatine kinase M, triosephosphate isomerase, phosphoglycerate mutase, cytochrome c oxidase, cytochrome b5, hydroxymethyl glutaryl CoA synthase, myoglobin, and 3,2‐trans‐enoyl‐CoA transferase. Additionally, the cytoskeletal protein actin was increased in the paced hearts. These results strongly support the notion that energy production is impaired and mitochondrial dysfunction is involved in the development of heart failure in the paced dog.
We have identified components of the signalling pathways along which apoptosis proceeds following the induction of heart failure in dogs. Apoptosis was also detected in the atria raising the possibility that, like human dilated cardiomyopathy, the molecular changes are global.
International guidelines recommend a multidisciplinary approach to the management of lung cancer due to the complexity of both patients and their disease and the multiple treatment options available. This care can be provided through patient discussion at multidisciplinary meetings where relevant medical and allied health staff formulate a consensus management plan taking all factors into consideration. This model can be extended further to include multidisciplinary clinics where the patient is present for assessment and discussion. However, conducting regular multidisciplinary meetings or clinics has significant time, resource and financial costs and therefore, it is important to assess the impact of multidisciplinary care.We aimed to review published evidence, from 2000 to 2019, to evaluate the impact of multidisciplinary care on lung cancer outcomes. There were 29 studies found, 11 evaluating multidisciplinary clinics, 14 studying multidisciplinary meetings and four where the model of care was not defined. There was only one randomised trial and three prospective studies, the remainder being retrospective studies. Despite limitations in trial design and confounding factors, overall, multidisciplinary care in lung cancer was associated with improvements in patient outcomes, in particular improved survival for all stages of lung cancer. Lung cancer patients managed in a multidisciplinary setting were more likely to receive active treatment and had improved utilisation of all treatment modalities: surgery, radiotherapy and chemotherapy. In addition, the treatment recommendations were more likely to be consistent with lung cancer management guidelines. These improved outcomes support the recommendations for a multidisciplinary approach to lung cancer care.
Canine rapid ventricular pacing produces a low output cardiomyopathic state which is similar to dilated cardiomyopathy. In this study dogs were paced at 245 beats per minute (bpm) for 3±4 weeks until signs of heart failure were apparent. Unpaced dogs were used as controls. A previous study identified myocardial protein changes in the pH region 4±7 following ventricular pacing by using two-dimensional electrophoresis (2-DE) (Heinke et al., Electrophoresis 1998. Many of these proteins were associated with mitochondria, energy metabolism within the cardiomyocyte, the cytoskeleton and calcium cycling. The present study aimed to examine the proteins migrating in the more basic region of the 2-DE pattern using immobilised pH gradient 3±10 strips to separate myocardial proteins. The expression of 31 proteins was altered in the paced myocardium: 21 were decreased and 10 increased. Following the identification of 23 of these spots by either amino acid compositional analysis or peptide mass fingerprinting or a combination of both, we confirm that many of the proteins whose expression is altered following ventricular pacing are associated with the mitochondria and energy production within the cardiomyocyte, including creatine kinase M, triosephosphate isomerase, phosphoglycerate mutase, cytochrome c oxidase, cytochrome b5, hydroxymethyl glutaryl CoA synthase, myoglobin, and 3,2-trans-enoyl-CoA transferase. Additionally, the cytoskeletal protein actin was increased in the paced hearts. These results strongly support the notion that energy production is impaired and mitochondrial dysfunction is involved in the development of heart failure in the paced dog.
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