Heart rate reduction via selective 'funny' channel blockers

The 'funny' current, first described in cardiac pacemaker cells almost 30 years ago, is a key player in the generation of pacemaker activity and the autonomic modulation of heart rate. Because of these specific functions, a search for molecules able to interfere selectively with the 'funny' current was undertaken soon after its discovery, with the aim of developing tools for the pharmacological control of heart rate. This search has succeeded in generating a new class of drugs, the heart rate-reducing agents, which act through specific blockade of f-channels; one of these drugs, ivabradine, is presently marketed against stable angina. Because of their many functions in heart and other tissues, pharmacological utilization of "funny" channel properties is an exciting new frontier open to further developments.     

Depression and anxiety levels in therapy-naive patients with inflammatory bowel disease and cancer of the colon

AIM： To assess whether depression and anxiety are more expressed in patients with the first episode of inflammatory bowel disease （IBD） than in individuals with newly discovered cancer of the colon （CCa）.
METHODS： A total of 32 patients with IBD including 13 males and 19 females, aged 27 to 74, and 30 patients with CCa including 20 males and 10 females, aged 39-78, underwent a structured interview, which comprised Hamilton＇s Depression Rating Inventory, Hamilton＇s Anxiety Rating Inventory and Paykel＇s Stressful Events Rating Scale.
RESULTS： Patients of the IBD group expressed both depression and anxiety. Depressive mood, sense of guilt, psychomotor retardation and somatic anxiety were also more pronounced in IBD patients. The discriminant function analysis revealed the total depressive score was of high importance for the classification of a newly diagnosed patient into one of the groups.
CONCLUSION： Newly diagnosed patients with IBD have higher levels of depression and anxiety. Moreover, a psychiatrist in the treatment team is advisable from the beginning.     

Flt3-dependent transformation by inactivating c-Cbl mutations in AML

In acute myeloid leukemia (AML), mutational activation of the receptor tyrosine kinase (RTK) Flt3 is frequently involved in leukemic transformation. However, little is known about a possible role of highly expressed wild-type Flt3 in AML. The proto-oncogene c-Cbl is an important regulator of RTK signaling, acting through its ubiquitin ligase activity and as a platform for several signaling adaptor molecules. Here, we analyzed the role of c-Cbl in Flt3 signal transduction and myeloid transformation. C-Cbl physically interacted with Flt3 and was tyrosine phosphorylated in the presence of Flt3-ligand (FL). Overexpression of a dominant-negative form of c-Cbl (Cbl-70Z) inhibited FL-induced Flt3 ubiquitylation and internalization, indicating involvement of c-Cbl in Flt3 signaling. DNA sequencing of AML bone marrow revealed a case with a c-Cbl point mutation (Cbl-R420Q). Cbl-R420Q inhibited Flt3 internalization and ubiquitylation. Coexpression of Cbl-R420Q or Cbl-70Z with Flt3 induced cytokine-independent growth and survival of 32Dcl3 cells in the absence of FL. Also, the mutant Cbl proteins altered the amplitude and duration of Flt3-dependent signaling events. Our results indicate an important role of Cbl proteins in Flt3 signal modulation. Also, the data suggest a novel mechanism of leukemic transformation in AML by mutational inactivation of negative RTK regulators.     

The Hedgehog receptor Patched controls lymphoid lineage commitment

A first step in hematopoiesis is the specification of the lymphoid and myeloid lineages from multipotent progenitor cells in the bone marrow. Using a conditional ablation strategy in adult mice, we show that this differentiation step requires Patched (Ptch), the cell surface-bound receptor for Hedgehog (Hh). In the absence of Ptch, the development of T- and B-lymphoid lineages is blocked at the level of the common lymphoid progenitor in the bone marrow. Consequently, the generation of peripheral T and B cells is abrogated. Cells of the myeloid lineage develop normally in Ptch mutant mice. Finally, adoptive transfer experiments identified the stromal cell compartment as a critical Ptch-dependent inducer of lymphoid versus myeloid lineage commitment. Our data show that Ptch acts as a master switch for proper diversification of hematopoietic stem cells in the adult organism.     

Blood coagulation factor XII--a neglected player in stroke pathophysiology

Ischemic stroke is a devastating disease which, in most cases, is caused by thrombotic occlusion of brain arteries. The molecular mechanisms involved in microvascular thrombus formation during focal cerebral ischemia are not well understood. As a consequence, the current antithrombotic drugs used to treat acute stroke or prevent stroke recurrence either show limited efficacy or put patients at risk for serious bleeding complications. The serine protease blood coagulation factor XII (FXII) initiates the intrinsic pathway of coagulation which, together with the extrinsic pathway, culminates in the formation of fibrin. A physiological function of FXII in clot formation and hemostasis in vivo has been questioned for more than 50 years. This was mainly due to the fact that hereditary FXII deficiency does not induce any bleeding phenotype in humans. However, recent studies in transgenic mice challenged this concept by demonstrating that FXII deficiency prevents pathological thrombus formation, but does not affect regular hemostasis. These findings entailed investigations in relevant disease models of thromboembolism including ischemic stroke. The present review summarizes the pathophysiological role of FXII in experimental cerebral ischemia and highlights novel therapeutic strategies based on FXII inhibition.     

Endoscopic optical coherence tomography device for forward imaging with broad field of view

One current challenge of studying human tympanic membranes (TM) with optical coherence tomography (OCT) is the implementation of optics that avoid direct contact with the inflamed tissue. At the moment, no commercial device is available. We report an optics design for contactless forward imaging endoscopic optical coherence tomography (EOCT) with a large working distance (WD) and a broad field of view (FOV) by restricting the overall diameter of the probe to be small (3.5 mm), ensuring a sufficient numerical aperture. Our system uses a gradient-index (GRIN) relay lens and a GRIN objective lens, and executes a fan-shaped optical scanning pattern. The WD and FOV can be adjusted by manually changing the distance between the triplet and the GRIN relay lens. The measured lateral resolution is ～28 μm at a WD of 10 mm with a FOV of 10 mm. Additionally, a camera and an illumination beam path were implemented within the probe for image guidance during investigations of the TM. We demonstrated the performance of the EOCT design by 3-D imaging of a human TM ex vivo and in vivo with a k-linear spectral domain OCT system.