103 OVARIAN STIMULATION OF ANESTROUS CATS WITH FOLLICLE-STIMULATING HORMONE IMPROVES OOCYTE QUALITY AND DEVELOPMENTAL CAPABILITY AFTER PARTHENOGENETIC ACTIVATION

The domestic cat is a valuable model for developing assisted reproductive technologies in endangered felids. However, the in vitro production of cat embryos is negatively affected during the anestrous season. It seems that a low FSH level or the few FSH receptors in the granulosa cells might affect oocyte quality. The objective of this research was to evaluate the effect of ovarian stimulation of anestrous cats with FSH on oocyte quality and developmental capability after parthenogenetic activation. For this, two experimental groups were made. The first (FSH group) consisted of 9 anestrous cats treated with a subcutaneous dose of 5 mg of porcine FSH, every 24 h, for 4 days. The second (control group) consisted of 10 untreated anestrous cats. The ovaries were recovered by ovariohysterectomy. Cumulus-oocyte complexes (COCs) were collected by slicing of the ovaries and classified morphologically as grade I (excellent), grade II (good), grade III (fair), and grade IV (poor) quality. Grade I and II COCs were matured in vitro during 30 h and matured oocytes were used for parthenogenetic activation. Matured oocytes were activated using 7% ethanol for 5 min, followed by incubation in 10 μg mL–1 cycloheximide and 5 μg mL–1 cytochalasin B for 5 h. Presumed zygotes were in vitro cultured in SOF for 8 days, and blastocyst and hatching blastocyst rates were assessed. The relative expression of pluripotency (OCT4, SOX2, and NANOG) and differentiation markers (CDX2 and GATA6) were evaluated by RT-qPCR in the blastocysts. The results were normalized using the geometric mean of GAPDH and SDHA. Statistical analysis was performed using the Wilcoxon non-parametric test. A total (mean ± s.d.) of 741 COCs (82.33 ± 36.61 per cat) were recovered from the FSH group and 660 COCs (66 ± 20.67 per cat) from the control group (P > 0.05). The FSH group had a higher rate of grade I COCs and a lower rate of grade III and IV COCs (22.28% and 50.62%, respectively) than the control group (13.2% and 60.08%, respectively; P < 0.05). However, no significant differences were found in grade II COCs between FSH (26.21%) and control groups (27.01%; P > 0.05). Thereafter, 190 matured oocytes were activated in the FSH group and 198 in the control group. The FSH group had higher blastocyst and hatching blastocyst rates (30.52% and 13.15%, respectively) than the control group (13.13% and 1.01% respectively; P < 0.05). The blastocysts from the FSH group had a higher cell number (± s.d.) than their counterparts from the control group (199.9 ± 53.6 and 121 ± 34.91, respectively; P < 0.05). Furthermore, the blastocysts from FSH group had an increased relative expression of OCT4 and GATA6 (P < 0.05). In conclusion, ovarian stimulation of anestrous cats with FSH improves oocyte quality and embryo developmental capability, which agrees with an increase in relative expression of OCT4 and GATA6.

Hippocampal structural and functional changes associated with electroconvulsive therapy response

Previous animal models and structural imaging investigations have linked hippocampal neuroplasticity to electroconvulsive therapy (ECT) response, but the relationship between changes in hippocampal volume and temporal coherence in the context of ECT response is unknown. We hypothesized that ECT response would increase both hippocampal resting-state functional magnetic resonance imaging connectivity and hippocampal volumes. Patients with major depressive disorder (n=19) were scanned before and after the ECT series. Healthy, demographically matched comparisons (n=20) were scanned at one-time interval. Longitudinal changes in functional connectivity of hippocampal regions and volumes of hippocampal subfields were compared with reductions in ratings of depressive symptoms. Right hippocampal connectivity increased (normalized) after the ECT series and correlated with depressive symptom reduction. Similarly, the volumes of the right hippocampal cornu ammonis (CA2/3), dentate gyrus and subiculum regions increased, but the hippocampal subfields were unchanged relative to the comparison group. Connectivity changes were not evident in the left hippocampus, and volume changes were limited to the left CA2/3 subfields. The laterality of the right hippocampal functional connectivity and volume increases may be related to stimulus delivery method, which was predominately right unilateral in this investigation. The findings suggested that increased hippocampal functional connectivity and volumes may be biomarkers for ECT response.

Soft-x-ray harmonic comb from relativistic electron spikes

We demonstrate a new high-order harmonic generation mechanism reaching the "water window" spectral region in experiments with multiterawatt femtosecond lasers irradiating gas jets. A few hundred harmonic orders are resolved, giving μJ/sr pulses. Harmonics are collectively emitted by an oscillating electron spike formed at the joint of the boundaries of a cavity and bow wave created by a relativistically self-focusing laser in underdense plasma. The spike sharpness and stability are explained by catastrophe theory. The mechanism is corroborated by particle-in-cell simulations.

Effect of lattice structure on energetic electron transport in solids irradiated by ultraintense laser pulses

The effect of lattice structure on the transport of energetic (MeV) electrons in solids irradiated by ultraintense laser pulses is investigated using various allotropes of carbon. We observe smooth electron transport in diamond, whereas beam filamentation is observed with less ordered forms of carbon. The highly ordered lattice structure of diamond is shown to result in a transient state of warm dense carbon with metalliclike conductivity, at temperatures of the order of 1-100 eV, leading to suppression of electron beam filamentation.

Modified proton radiography arrangement for the detection of ultrafast field fronts

The experimental arrangement for the investigation of high-field laser-induced processes using a broadband proton probe beam has been modified to enable the detection of the ultrafast motion of field fronts. It is typical in such experiments for the target to be oriented perpendicularly with respect to the principal axis of the probe beam. It is demonstrated here, however, that the temporal imaging properties of the diagnostic arrangement are altered drastically by placing the axis (or plane) of the target at an oblique angle to the transverse plane of the probe beam. In particular, the detection of the motion of a laser-driven field front along a wire at a velocity of (0.95+/-0.05)c is described.

Laser-driven ultrafast field propagation on solid surfaces

The interaction of a 3x10;{19} W/cm;{2} laser pulse with a metallic wire has been investigated using proton radiography. The pulse is observed to drive the propagation of a highly transient field along the wire at the speed of light. Within a temporal window of 20 ps, the current driven by this field rises to its peak magnitude approximately 10;{4} A before decaying to below measurable levels. Supported by particle-in-cell simulation results and simple theoretical reasoning, the transient field measured is interpreted as a charge-neutralizing disturbance propagated away from the interaction region as a result of the permanent loss of a small fraction of the laser-accelerated hot electron population to vacuum.