Electrical remodeling in hearts from a calcium-dependent mouse model of hypertrophy and failure: complex nature of K+ current changes and action potential duration

OBJECTIVES: This study was designed to identify possible electrical remodeling (ER) in transgenic (Tg) mice with over-expressed L-type Ca(2+) channels. Transient outward K(+) current (I(to)) and action potential duration (APD) were studied in 2-, 4-, 8-, and 9- to 12-month-old mice to determine linkage to ventricular remodeling (VR), ER, and heart failure (HF). BACKGROUND: Prolongation of APD and reduction in current density of I(to) are thought to be hallmarks of VR and HF. Mechanisms are not understood. METHODS: Patch-clamp, perfused hearts, echocardiography, and Western blots were employed using 2-, 4-, 8-, and 9- to 12-month-old Tg mice. RESULTS: Transgenic mice developed slow VR statistically manifesting at four months and continuing through death at 12 to 14 months, despite a slight up-regulation of I(to). A slight decrease or no change in APD was observed up to eight months; however, at 9 to 12 months, a small increase in APD was detected. Early afterdepolarizations were observed after application of 4-aminopyridine in Tg mice. No change was detected in protein of Kv4.3 and Kv4.2 up to eight months. At 9 to 12 months, Tg mice showed a slight decrease (41.4 +/- 6.9%, p < 0.05) in Kv4.2, consistent with a decrease in I(to). Surprisingly, Kv1.4 (the "fetal" K(+)-channel form) was up-regulated, and restitution of I(to) was slowed. Echocardiography revealed cardiac enlargement with impaired chamber function in hearts that were taken from the older animals. CONCLUSIONS: Contrary to accepted dogma, APD and I(to) in a mouse model of hypertrophy and HF are not hallmarks of pathophysiology. We suggest that [Ca(2+)](i) (i.e., [Ca(2+)] concentration) is the primary factor in triggering cardiac enlargement and arrhythmogenesis.     

Valsalva sinus pseudoaneurysm causes acute myocardial infarction and stroke simultaneously

Spontaneous Valsalva sinus pseudoaneurysm is a rare and highly lethal condition. Below we present a clinical case of a young woman with spontaneous Valsalva sinus pseudoaneurysm diagnosed presenting with acute myocardial infarction (AMI) and ischemic stroke.     

Preoperative and early postoperative magnetic resonance imaging in two cases of childhood choroid plexus carcinoma

We present and illustrate the MRI appearances of two children with choroid plexus carcinoma. The MRI characteristics of these rare tumours are reviewed. Since total surgical resection is a significant prognostic factor, early postoperative MRI was performed in both cases to ensure surgical clearance. In one case a complete resection was documented and this patient remains well at short-term follow-up. Residual tumour was noted in the second case, but despite "second look" surgery there was subsequent local relapse.     

Masson's tumour in the right parietal lobe after stereotactic radiosurgery for cerebellar AVM: case report and review

We present a 50-year-old patient who had undergone stereotactic radiosurgery for a cerebellar vermian arteriovenous malformation. On routine surveillance MR imaging a lesion suggestive of a meningioma was demonstrated and removed. Histologically it was found to be intravascular papillary endothelial hyperplasia (Masson's tumour). The characteristic radiological and histological findings are presented. Aspects of management of this rare tumour are discussed. Given that cases are often found in combination with a vascular abnormality, we discuss the possibility of a change in local haemodynamics after radiosurgery promoting development of this tumour.     

Giant cystic intracranial chondroma of the falx with review of literature

Rare cases of intracranial chondromas have been documented in the literature, often after complete surgical excision. We describe a case of giant intracranial tumor at post‐mortem examination of a man who had survived 48 years after a partial debulking. Histological examination revealed a chondroid tumor with no significant pleomorphism and central cystic degeneration. Our case illustrates the benignity of the intracranial chondroma and to our knowledge, is one of the longest surviving and largest cases found after incomplete removal.     

Assessment of β-amyloid deposits in human brain: a study of the BrainNet Europe Consortium

β-Amyloid (Aβ) related pathology shows a range of lesions which differ both qualitatively and quantitatively. Pathologists, to date, mainly focused on the assessment of both of these aspects but attempts to correlate the findings with clinical phenotypes are not convincing. It has been recently proposed in the same way as ι and α synuclein related lesions, also Aβ related pathology may follow a temporal evolution, i.e. distinct phases, characterized by a step-wise involvement of different brain-regions. Twenty-six independent observers reached an 81% absolute agreement while assessing the phase of Aβ, i.e. phase 1 = deposition of Aβ exclusively in neocortex, phase 2 = additionally in allocortex, phase 3 = additionally in diencephalon, phase 4 = additionally in brainstem, and phase 5 = additionally in cerebellum. These high agreement rates were reached when at least six brain regions were evaluated. Likewise, a high agreement (93%) was reached while assessing the absence/presence of cerebral amyloid angiopathy (CAA) and the type of CAA (74%) while examining the six brain regions. Of note, most of observers failed to detect capillary CAA when it was only mild and focal and thus instead of type 1, type 2 CAA was diagnosed. In conclusion, a reliable assessment of Aβ phase and presence/absence of CAA was achieved by a total of 26 observers who examined a standardized set of blocks taken from only six anatomical regions, applying commercially available reagents and by assessing them as instructed. Thus, one may consider rating of Aβ-phases as a diagnostic tool while analyzing subjects with suspected Alzheimer’s disease (AD). Because most of these blocks are currently routinely sampled by the majority of laboratories, assessment of the Aβ phase in AD is feasible even in large scale retrospective studies.