Transgenic Mice in the Search for Development-related Genes: Application for the Studies of Congenital Anomalies*

Transgenic mice technology in conjunction with other molecular biological and embryo manipulation techniques has made it possible to manipulate the mouse genome to elucidate the molecular mechanisms of normal and abnormal embryonic development. This genetic technology also permits the isolation of novel genes involved in developmental events. It has and certainly will greatly contribute to the better understanding of the pathogenesis of congenital anomalies. However, the majority of congenital anomalies in humans occur from multifactorial causes including not only genetic but also various environmental factors. Thus, transgenic mice can be utilized as an excellent genetic tool on which all the available conventional teratological techniques and informations are concentrated to elucidate molecular mechanisms and the holistic picture of congenital anomaly formation.     

Endoscopically Treated Angiodysplasia of the Ileum

Abstract: Angiodysplasia has been recognized as one of the main causes of gastrointestinal bleeding, but few such lesions have been found, or treated by an endoscopic procedure, in the ileum. We endoscopically identified angiodysplasia in the ileum of an 85-year-old female who had tarry stools. Because she had severe aortic stenosis, we treated the lesion endoscopically by combining polidocanol injection and electrocoagulation with hot biopsy forceps. This method was considered to be safe and efficient, especially for lesions in the thin walled intestine.     

Computer Simulation of Cardiac Pacing

A mathematical model of the cardiac conduction system, including external pacemakers, has been developed. The heart is modeled as a network in which the impulse propagation is described by differential equations; several arrhythmia-generating mechanisms, such as modulated parasystole, reflection, macro and micro re-entry and block, can be simulated. Different kinds of pacemaker modes have been incorporated in the model, thus making it possible to simulate the interaction between the heart and the pacemaker. The model can be tuned by the user according to electrophysiological data so that pacemaker programs can be tested under different underlying conditions. During a simulation, the program generates ECG signals and pacemaker diagnostic diagrams. This model can be used for training and testing, and also as a support system when searching for the optimal pacing therapy for a particular patient.