Calcium Signaling and Contractility in Cardiac Myocyte of Wolframin Deficient Rats.

Wolframin (Wfs1) is a membrane protein of the sarco/endoplasmic reticulum. Wfs1 mutations are responsible for the Wolfram syndrome, characterized by diabetic and neurological symptoms. Although Wfs1 is expressed in cardiac muscle, its role in this tissue is not clear.

Ryanodine receptor gating controls generation of diastolic calcium waves in cardiac myocytes.

The role of cardiac ryanodine receptor (RyR) gating in the initiation and propagation of calcium waves was investigated using a mathematical model comprising a stochastic description of RyR gating and a deterministic description of calcium diffusion and sequestration. We used a one-dimensional array of equidistantly spaced RyR clusters, representing the confocal scanning line, to simulate the formation of calcium sparks. Our model provided an excellent description of the calcium dependence of the frequency of diastolic calcium sparks and of the increased tendency for the production of calcium waves after a decrease in cytosolic calcium buffering.

Calcium spike variability in cardiac myocytes results from activation of small cohorts of ryanodine receptor 2 channels.

In mammalian cardiac myocytes, the elementary calcium releases triggered by step voltage stimuli manifest either as solitary or as twin spikes that vary widely in kinetics and amplitude for unknown reasons. Here we examined the variability of calcium spikes measured using line-scanning confocal microscopy in patch-clamped rat ventricular myocytes. Amplitude distributions of the single and of the first of twin spikes were broader than those of the second spikes.

Proliferative potential and phenotypic analysis of long-term cultivated human granulosa cells initiated by addition of follicular fluid.

Purpose: The aim of this study was to develop and optimize a strategy for long-term cultivation of luteinizing human granulosa cells (GCs).

Methods: GCs were cultivated in DMEM/F12 medium supplemented with 2% fetal calf serum. In vitro proliferation of GCs was supported by follicular fluid as well as FSH and growth factors.

Comparison of follicular fluid and serum levels of Inhibin A and Inhibin B with calculated indices used as predictive markers of Ovarian Hyperstimulation Syndrome in IVF patients.

Background: Ovarian Hyperstimulation Syndrome (OHSS) is a severe health complication observed in some patients undergoing hormonal stimulation during IVF. Presence of OHSS is often associated with a high count of growing follicles responding to FSH hyperstimulation. However, the number of responding follicles may not be sufficient enough to predict the onset and severity of OHSS.

Local calcium release activation by DHPR calcium channel openings in rat cardiac myocytes.

The principal role of calcium current in the triggering of calcium release in cardiac myocytes is well recognized. The mechanism of how calcium current (I(Ca)) controls the intensity of calcium release is not clear because of the stochastic nature of voltage-dependent gating of calcium channels (DHPRs) and of calcium-dependent gating of ryanodine receptors (RyRs). To disclose the relation between DHPR openings and the probability of calcium release, local calcium release activation by I(Ca) was investigated in rat ventricular myocytes using patch-clamp and confocal microscopy.

Follicular fluid and serum levels of inhibin A and pregnancy-associated plasma protein A in patients undergoing IVF.

Objective: To elucidate transport of intrafollicular proteins Inhibin A and pregnancy-associated plasma protein A (PAPP-A) across the follicular fluid (FF)/blood barrier.

Design: A retrospective study.

Setting: IVF lab at a university hospital, academic, and industrial research labs.

The cultivation of human granulosa cells.

The major functions of granulosa cells (GCs) include the production of steroids, as well as a myriad of growth factors to interact with the oocyte during its development within the ovarian follicle. Also FSH stimulates GCs to convert androgens (coming from the thecal cells) to estradiol by aromatase. However, after ovulation the GCs produce progesterone that may maintain a potential pregnancy.

Spatial and temporal Ca2+, Mg2+, and ATP2- dynamics in cardiac dyads during calcium release.

We have constructed a three-dimensional reaction-diffusion model of the mammalian cardiac calcium release unit. We analyzed effects of diffusion coefficients, single channel current amplitude, density of RyR channels, and reaction kinetics of ATP(2-) with Ca(2+) and Mg(2+) ions on spatiotemporal concentration profiles of Ca(2+), Mg(2+), and ATP(2-) in the dyadic cleft during Ca(2+) release. The model revealed that Ca(2+) concentration gradients persist near RyRs in the steady state.

Activation of calcium release assessed by calcium release-induced inactivation of calcium current in rat cardiac myocytes.

In mammalian cardiac myocytes, calcium released into the dyadic space rapidly inactivates calcium current (ICa). We used this Ca2+ release-dependent inactivation (RDI) of ICa as a local probe of sarcoplasmic reticulum Ca2+ release activation. In whole cell patch-clamped rat ventricular myocytes, Ca2+ entry induced by short prepulses from -50 mV to positive voltages caused suppression of peak ICa during a test pulse.

Improved implantation rate after chemical removal of the zona pellucida.

Objective: To evaluate the implantation rate achieved after chemical removal of the zona pellucida from day 5 human in vitro-derived embryos.

Design: Prospective, randomized, controlled study.

Setting: A tertiary care infertility clinic.