A comparison of culture and cooling for the short term preservation of in vivo derived dromedary camel embryos of varying morphological quality.

Despite recent advancements in the cryopreservation of dromedary camel embryos, widespread application of the technique is still limited by the need for specialised vitrification equipment and supplies. Temporary, liquid-phase embryo storage methods provide a useful tool for short-term preservation of camel embryos. In the current study, we compared the use of in vitro embryo culture with cold liquid storage in order to maintain both high- (Grade 1- Excellent and 2-Good) and low- (Grade 3- Moderate and 4-Poor) morphological grade Day-7 dromedary camel embryos in vitro for up to 3 days. Embryos were either cooled and placed in Hams-F10 medium supplemented with HEPES and 10% FBS and then kept at 4 °C; or placed in Hams-F10 supplemented with sodium bicarbonate and 10% FBS and then cultured in a humidified atmosphere of 6% CO2 at 37 °C before being assessed for viability at 24 h. In high-morphological grade embryos, both cold storage and culture supported 100% viability (maintenance of normal morphology) over this period (Cooled n = 22, Cultured n = 20). In low-morphological grade embryos, culture supported higher viability (16/18, 88.9%) than did cooling (4/18, 22.2%). We then evaluated the effect of up to 3 days of cold storage or culture on embryo morphological grade, diameter, and developmental competence following embryo transfer. High-grade embryos were divided between culture and cold storage; low-grade embryos were evaluated only after culture. Over 3 days of culture, both high- and low-grade embryos tended to either maintain or improve upon their initial morphological score (P < 0.05) and increased in diameter (P < 0.001). Embryos subjected to cooling tended to have reduced morphological scores by 48 h of storage and decreased in diameter by 72 h (P < 0.05). No significant influence of storage method (cooling vs. culture), duration (24-72 h), or embryo grade (high vs low) was observed on pregnancy establishment at Day-60 (22.2%-57.2% pregnancy rates for all treatments). Overall, rates of pregnancy establishment were similar for transferred cultured (n = 45) and cooled (n = 45) embryos (pregnancy rates at Day 18, 48% vs 51.1%; at Day 60, 37.7% vs 37.7%). Rates of embryonic loss also were similar (22.7% vs 26%). In conclusion, whilst similar rates of pregnancy and pregnancy loss were observed following the transfer of both cooled and cultured embryos held in vitro for up to 3 days, amongst the two methods, only embryo culture appears to provide a means of effectively preserving Day- 7 dromedary camel embryos with reduced morphological values in vitro. Considering these embryos appear to show poor tolerance to the cooling procedure and are unlikely candidates for vitrification, embryo culture may provide an effective method for deriving pregnancies from low-morphological grade embryos when immediate transfer is not possible on the day of flushing.

Correlated cerebral events between physically and sensory isolated pairs of subjects exposed to yoked circumcerebral magnetic fields.

In three different experiments pairs of unrelated people sitting in two different rooms were exposed simultaneously to different rates of circumcerebral rotations of weak, complex magnetic fields in order to produce "dynamic similarity". Quantitative electroencephalographic (QEEG) measurements were taken for one member of each pair in one room while the other sat in a closed chamber in another room and intermittently observed 5Hz, 8Hz, 10Hz, or 15Hz flashing lights. Reliable increases in QEEG power within specific frequencies over the right parietal region were observed during the similar-frequency light flashes when the shared temporal-spatial complexity of the circumcerebral rotating fields was based on 100ms, the average duration of normal microstates. The development of this experimental procedure could facilitate rational understanding of this class of "coincidence" phenomena.

Prenatal exposures to LTP-patterned magnetic fields: quantitative effects on specific limbic structures and acquisition of contextually conditioned fear.

Weak (<1 microT) complex magnetic fields (CMFs) may exert their behavioral influences through the hippocampus by resonating by accident or design with intrinsic electrical patterns. Rats were exposed prenatally to one of four intensities of a CMF (either <5 nanoTesla [nT], 10-50 nT, 50-500 nT, or 500-1000 nT) designed to interact with the process of Long-Term Potentiation (LTP) in the hippocampus. Rats then underwent testing in the forced swim, open field, and fear-conditioning procedures. The cell densities of all amygdaloid nuclei, specific hypothalamic structures, and the major regions of the hippocampus were quantified. Results showed that acquisition of conditioned fear was strongly inhibited in animals exposed to LTP-CMFs. Rats exposed to intensities above 10 nT showed decreased cell density in the CA2 fields of the hippocampus; more neurons were present in the CA1 fields of rats exposed to the 10-50 nT intensities compared to all other groups. A decrease in cell density in the medial preoptic nucleus was linearly dependent on field intensity. In the forced-swim test, swimming was decreased in rats that had been exposed to low (10-50 nT) and medium intensity (50-500 nT) LTP-CMFs in a manner consistent with monoamine modulation. In the open field, exposed rats were indistinguishable from controls. These findings support the hypothesis that continuous exposure during prenatal development to CMFs designed to simulate intrinsic LTP within the hippocampus can affect adult behaviors specific to this structure and produce quantitative alterations in neuronal density.

Wigner function approach to the quantum Brownian motion of a particle in a potential.

Recent progress in our understanding of quantum effects on the Brownian motion in an external potential is reviewed. This problem is ubiquitous in physics and chemistry, particularly in the context of decay of metastable states, for example, the reversal of the magnetization of a single domain ferromagnetic particle, kinetics of a superconducting tunnelling junction, etc. Emphasis is laid on the establishment of master equations describing the diffusion process in phase space analogous to the classical Fokker-Planck equation. In particular, it is shown how Wigner's [E. P. Wigner, Phys. Rev., 1932, 40, 749] method of obtaining quantum corrections to the classical equilibrium Maxwell-Boltzmann distribution may be extended to the dissipative non-equilibrium dynamics governing the quantum Brownian motion in an external potential V(x), yielding a master equation for the Wigner distribution function W(x,p,t) in phase space (x,p). The explicit form of the master equation so obtained contains quantum correction terms up to o(h(4)) and in the classical limit, h --> 0, reduces to the classical Klein-Kramers equation. For a quantum oscillator, the method yields an evolution equation coinciding in all respects with that of Agarwal [G. S. Agarwal, Phys. Rev. A, 1971, 4, 739]. In the high dissipation limit, the master equation reduces to a semi-classical Smoluchowski equation describing non-inertial quantum diffusion in configuration space. The Wigner function formulation of quantum Brownian motion is further illustrated by finding quantum corrections to the Kramers escape rate, which, in appropriate limits, reduce to those yielded via quantum generalizations of reaction rate theory.

Semiclassical master equation in Wigners phase space applied to Brownian motion in a periodic potential.

The quantum Brownian motion of a particle in a cosine periodic potential V(x)= -V{0}cos(x/x{0}) is treated using the master equation for the time evolution of the Wigner distribution function W(x,p,t) in phase space (x,p) . The dynamic structure factor, escape rate, and jump-length probabilities are evaluated via matrix continued fractions in the manner customarily used for the classical Fokker-Planck equation. The escape rate so yielded is compared with that given analytically by the quantum-mechanical reaction rate solution of the Kramers turnover problem. The matrix continued fraction solution substantially agrees with the analytic solution.

Thermally activated escape rate for a Brownian particle in a tilted periodic potential for all values of the dissipation.

The translational Brownian motion of a particle in a tilted washboard potential is considered. The dynamic structure factor and longest relaxation time are evaluated from the solution of the governing Langevin equation by using the matrix continued fraction method. The longest relaxation time is compared with the Kramers theory of the escape rate of a Brownian particle from a potential well as extended to the Kramers turnover region by Mel'nikov [Physics Reports 209, 1 (1991)]. It is shown that in the low temperature limit, the universal Mel'nikov expression for the escape rate provides a good estimate of the longest relaxation time for all values of dissipation including the very low damping (VLD), very high damping (VHD), and turnover regimes. For low barriers (where the Mel'nikov method is not applicable) and zero tilt, analytic equations for the relaxation times in the VLD and VHD limits are derived.

The diaphragma sellae: its relationship to the configuration of the pituitary gland.

One hundred sphenoid bones that were removed at autopsy from patients without apparent pituitary disease and with histologically normal pituitary glands were examined. In 46 specimens the diaphragma sellae was complete. The majority showed convex downward bowing below the diaphragmatic line in both the lateral and frontal planes while the remainder were straight, corresponding to the diaphragmatic line. In only one specimen was the diaphragma sellae convex upward in both planes. These findings suggest that upward displacement of the diaphragma sella as seen of coronal and sagittal computed tomography (CT) may provide early evidence of an expanding pituitary lesion. Twenty of 54 defective specimens had a defect that was larger than 80% of the length of the diaphragma sellae. There was a correlation between the size of the defect and the depth of the intrasellar cistern that resulted from the downward extension of the suprasellar cistern. Such variations may lead to confusion in CT interpretation. The pituitary infundibulum was at or behind the level of the midpoint of the diaphragma sellae in all specimens. In the presence of a defect, the infundibulum usually retained its relationship to the posterior rim of the defect, and therefore when the defect was large the infundibulum was found adjacent to the dorsum sellae.