Genetic Dissection of Epidermal Growth Factor Receptor Signaling during Luteinizing Hormone-Induced Oocyte Maturation

Recent evidence that luteinizing hormone (LH) stimulation of ovulatory follicles causes transactivation of the epidermal growth factor receptor (EGFR) has provided insights into the mechanisms of ovulation. However, the complete array of signals that promote oocyte reentry into the meiotic cell cycle in the follicle are still incompletely understood. To elucidate the signaling downstream of EGFR involved in oocyte maturation, we have investigated the LH responses in granulosa cells with targeted ablation of EGFR. Oocyte maturation and ovulation is disrupted when EGFR expression is progressively reduced. In granulosa cells from mice with either global or granulosa cell-specific disruption of EGFR signaling, LH-induced phosphorylation of MAPK3/1, p38MAPK, and connexin-43 is impaired. Although the LH-induced decrease in cGMP is EGFR-dependent in wild type follicles, LH still induces a decrease in cGMP in Egfrdelta/f Cyp19-Cre follicles. Thus compensatory mechanisms appear activated in the mutant. Spatial propagation of the LH signal in the follicle also is dependent on the EGF network, and likely is important for the control of signaling to the oocyte. Thus, multiple signals and redundant pathways contribute to regulating oocyte reentry into the cell cycle

Calcium ion currents mediating oocyte maturation events

During maturation, the last phase of oogenesis, the oocyte undergoes several changes which prepare it to be ovulated and fertilized. Immature oocytes are arrested in the first meiotic process prophase, that is morphologically identified by a germinal vesicle. The removal of the first meiotic block marks the initiation of maturation. Although a large number of molecules are involved in complex sequences of events, there is evidence that a calcium increase plays a pivotal role in meiosis re-initiation. It is well established that, during this process, calcium is released from the intracellular stores, whereas less is known on the role of external calcium entering the cell through the plasma membrane ion channels. This review is focused on the functional role of calcium currents during oocyte maturation in all the species, from invertebrates to mammals. The emerging role of specific L-type calcium channels will be discussed

Methods for providing diagnostic information using endocardial surface data for a patient’s heart - U.S. patent 7,828,735

Methods for providing diagnostic information using endocardial surface data for a patient\u27s heart are described herein. In some embodiments, endocardial surface data for the left ventricle of a heart is received. The endocardial surface data represents the endocardial surface of the left ventricle at multiple times over a heartbeat and is obtained using a volumetric imaging application. A representation in prolate spheroidal coordinates of the endocardial surface of the left ventricle at least a portion of the multiple times is generated using the endocardial surface data. The prolate spheroidal coordinates include a longitudinal angular coordinate .mu., a circumferential angular coordinate .theta., and a coordinate .lamda. as a function of longitudinal angular coordinate .mu. and circumferential angular coordinate .theta.. A measure that provides diagnostic information related to the left ventricle is computed based at least on part on the value of coordinate .lamda.

Functional Imaging and Modeling of the Heart. FIMH 2005. Lecture Notes in Computer Science

Susan L. Freudzon (as Susan L. Herz, with Qi Duan, Elsa D. Angelini, Olivier Gerard, Pascal Allain, Christopher M. Ingrassia, Kevin D. Costa, Jeffrey W. Holmes, Shunichi Homma, and Andrew F. Laine) is a contributing author, Tracking of LV Endocardial Surface on Real-Time Three-Dimensional Ultrasound with Optical Flow. Chapter Abstract: Matrix-phased array transducers for real-time three-dimensional ultrasound enable fast, non-invasive visualization of cardiac ventricles. Segmentation of 3D ultrasound is typically performed at end diastole and end systole with challenges for automation of the process and propagation of segmentation in time. In this context, given the position of the endocardial surface at certain instants in the cardiac cycle, automated tracking of the surface over the remaining time frames could reduce the workload of cardiologists and optimize analysis of volume ultrasound data. In this paper, we applied optical flow to track the endocardial surface between frames of reference, segmented via manual tracing or manual editing of the output from a deformable model. To evaluate optical-flow tracking of the endocardium, quantitative comparison of ventricular geometry and dynamic cardiac function are reported on two open-chest dog data sets and a clinical data set. Results showed excellent agreement between optical flow tracking and segmented surfaces at reference frames, suggesting that optical flow can provide dynamic “interpolation” of a segmented endocardial surface. Keywords: Root Mean Square Error, Optical Flow, Deformable Model, Endocardial Surface, Ventricular Geometryhttps://digitalcommons.fairfield.edu/engineering-books/1033/thumbnail.jp

Microinjection of Follicle-Enclosed Mouse Oocytes

The mammalian oocyte develops within a complex of somatic cells known as a follicle, within which signals from the somatic cells regulate the oocyte, and signals from the oocyte regulate the somatic cells. Because isolation of the oocyte from the follicle disrupts these communication pathways, oocyte physiology is best studied within an intact follicle. Here we describe methods for quantitative microinjection of follicle-enclosed mouse oocytes, thus allowing the introduction of signaling molecules as well as optical probes into the oocyte within its physiological environment