Effects of polyethylene glycol and a synthetic ice blocker during vitrification of immature porcine oocytes on survival and subsequent embryo development

We evaluated the effects of polyethylene glycol (PEG) and Supercool X‐1000 (SC) as supplements during the vitrification of immature cumulus‐enclosed porcine oocytes in a solution based on 17.5% ethylene glycol + 17.5% propylene glycol. After warming, the oocytes were subjected to in vitro maturation, fertilization and embryo culture. In Experiment 1, equilibration and vitrification solutions were supplemented with or without 2% (w/v) PEG (PEG+ and PEG‐, respectively). The survival rate, cleavage and blastocyst development were similar between PEG+ and PEG‐ groups; however, all values were lower than those in the non‐vitrified control. In Experiment 2, vitrification solution was supplemented with or without 1% (v/v) SC (SC+ and SC‐, respectively). The percentages of survival and blastocyst development were similar between SC+ and SC‐ groups but lower than those in the non‐vitrified control. The percentage of cleavage in the SC‐ group was significantly lower than the control and the SC+ groups, which were in turn similar to one another. In both experiments, the cell numbers in blastocysts were not significantly different among the non‐vitrified and vitrified groups. In conclusion, PEG did not improve oocyte survival and embryo development, whereas SC improved the ability of surviving oocytes to cleave but not to develop into blastocysts.     

Preserved feedforward but impaired top-down processes in the vegetative state

Frontoparietal cortex is involved in the explicit processing (awareness) of stimuli. Frontoparietal activation has also been found in studies of subliminal stimulus processing. We hypothesized that an impairment of top-down processes, involved in recurrent neuronal message-passing and the generation of long-latency electrophysiological responses, might provide a more reliable correlate of consciousness in severely brain-damaged patients, than frontoparietal responses. We measured effective connectivity during a mismatch negativity paradigm and found that the only significant difference between patients in a vegetative state and controls was an impairment of backward connectivity from frontal to temporal cortices. This result emphasizes the importance of top-down projections in recurrent processing that involve high-order associative cortices for conscious perception.     

Oesophageal strictures in cats associated with doxycycline therapy

Four cases of oesophageal stricture subsequent to doxycycline administration are reported. All cases were young to middle age (median age 3 years; range 1-7 years), and either domestic shorthair or domestic longhair breed. In all cases the predominant clinical sign was regurgitation, which developed at variable times after doxycycline administration. In all cases the reason for doxycycline use was treatment or prophylaxis of suspected infections (Mycoplasma haemofelis, Chlamydophila felis or Bordetella bronchiseptica), and the duration of therapy was variable. In one case the stricture was definitively diagnosed at post mortem examination, in the three other cases, definitive diagnosis was by endoscopy. Balloon dilation was successful in the three cases that were treated. This is the largest case series, to date, of oesophageal disease in cats associated with doxycycline administration. Caution should be exercised when administering oral medication to cats, especially doxycycline, and should be accompanied either by a water or food swallow.     

Neurobiological substrates of dread

Given the choice of waiting for an adverse outcome or getting it over with quickly, many people choose the latter. Theoretical models of decision-making have assumed that this occurs because there is a cost to waiting-i.e., dread. Using functional magnetic resonance imaging, we measured the neural responses to waiting for a cutaneous electric shock. Some individuals dreaded the outcome so much that, when given a choice, they preferred to receive more voltage rather than wait. Even when no decision was required, these extreme dreaders were distinguishable from those who dreaded mildly by the rate of increase of neural activity in the posterior elements of the cortical pain matrix. This suggests that dread derives, in part, from the attention devoted to the expected physical response and not simply from fear or anxiety. Although these differences were observed during a passive waiting procedure, they correlated with individual behavior in a subsequent choice paradigm, providing evidence for a neurobiological link between the experienced disutility of dread and subsequent decisions about unpleasant outcomes.     

Response of Scotian Shelf silver hake (Merluccius bilinearis) to environmental variability

Commercially‐exploited fish populations are not only shaped by fishing pressure, but also by the dynamics of their environment. By quantifying the influence of environmental variability, fisheries management advice can be improved and uncertainties reduced. To this end, we developed statistical models of the response of Scotian Shelf silver hake stock metrics to variability in zooplankton community composition and phenology over the past 18 years and in the physical environment since 1985. Dominant modes of variability in these pelagic habitat indicators were characterized using principal component analysis, and the relationships of silver hake condition, abundance, and recruitment to pelagic habitat variability were assessed using generalized additive models. Condition was largely modulated by the onset and duration of the spring bloom, which controls food availability. In contrast, adult abundance was governed by composition of the zooplankton community and bottom‐water temperature, which dictates the distribution of silver hake. Finally, recruitment was affected by both thermal conditions and food availability. Our results presented here form the basis for qualitative assessment of ecosystem attributes and the influence on silver hake stock productivity.