Risk‐preference differentiates orbitofrontal cortex responses to freely chosen reward outcomes

To successfully evaluate potential courses of action and choose the most favorable, we must consider the outcomes that may result. Many choices involve risk, our assessment of which may lead us to success or failure in matters financial, legal or health‐related. The orbitofrontal cortex (OFC) has been implicated as critical for evaluating choices based on risk. To measure how outcomes of risky decisions are represented in the OFC, we recorded the electrophysiological activity of single neurons while rats made behavioral responses to obtain rewards under conditions of either certainty or risk. Rats exhibited different risk‐preferences when given the opportunity to choose. In risk‐preferring rats, OFC responses were enhanced following the delivery of large rewards obtained under risk compared with smaller, certain rewards and reward omission. However, in risk‐neutral rats, neurons showed similarly enhanced responses to both large rewards obtained under risk and smaller, certain rewards compared with reward omission. Thus, the responses of OFC neurons reflected the subjective evaluation of outcomes in individuals with different risk‐preferences. Such enhanced neural responding to risky rewards may serve to bias individuals towards risk‐preference in decision‐making.     

Isolation of microsatellite loci from Rhamnus pirifolia

Rhamnus pirifolia Greene (Rhamnaceae), the island redberry, is a small evergreen tree endemic to the California Channel Islands and Guadalupe Island, Mexico. Nine polymorphic microsatellite loci were isolated from the taxon and were screened for variability in populations from three California Channel Islands. Moderate levels of variability were observed, with mean numbers of alleles per locus ranging from 1.3 to 4.7. The mean observed and expected heterozygosities ranged from 0.01 to 0.53 and 0.01 to 0.56, respectively. These new loci will be useful in conservation genetic and evolutionary studies within Rhamnus.     

The prevalence of cobedding and SIDS-related child care practices in twins

Sudden unexplained and unexpected death in twins has not been well studied, particularly in relation to the common practice of sleeping twin infants together in the same cot (cobedding). Postal surveys of 109 mothers of twins were undertaken when the infants were 6 weeks, 4 months, and 8 months of age to determine the prevalence of cobedding, infant care practices related to sudden infant death syndrome (SIDS), and the mother’s knowledge of SIDS risk factors. SIDS risk factor knowledge was similar to an earlier survey of singletons in 2005. At 6 weeks, 76% of infants usually slept on the back; this changed to 86% at 4 months and 73% at 8 months. At 6 weeks, 52% usually cobedded with their twin all or part of the time. At 4 and 8 months, this had reduced to 31% and 10%, respectively. Side-by-side cobedding configurations were predominant at 6 weeks, with feet-to-feet configurations increasing as the infants grew older. Breastfeeding was reported in 83%, 61% and 31% of infants at 6 weeks, 4 months and 8 months, respectively. Pacifier use was reported in 38%, 50% and 33% at the respective surveys. As the age of the twins increased, mothers were significantly more likely to be concerned about deformational plagiocephaly in Twin 1 than in Twin 2. Conclusion: Despite a lack of evidence of the risks or benefits of cobedding, this practice was very popular, especially in the younger infants. More research is needed to establish the safety of cobedding in relation to the risk of SIDS.     

Generation of HIV-1 Resistant and Functional Macrophages From Hematopoietic Stem Cell�Cderived Induced Pluripotent Stem Cells

Induced pluripotent stem cells (iPSCs) have radically advanced the field of regenerative medicine by making possible the production of patient-specific pluripotent stem cells from adult individuals. By developing iPSCs to treat HIV, there is the potential for generating a continuous supply of therapeutic cells for transplantation into HIV-infected patients. In this study, we have used human hematopoietic stem cells (HSCs) to generate anti-HIV gene expressing iPSCs for HIV gene therapy. HSCs were dedifferentiated into continuously growing iPSC lines with four reprogramming factors and a combination anti-HIV lentiviral vector containing a CCR5 short hairpin RNA (shRNA) and a human/rhesus chimeric TRIM5α gene. Upon directed differentiation of the anti-HIV iPSCs toward the hematopoietic lineage, a robust quantity of colony-forming CD133⁺ HSCs were obtained. These cells were further differentiated into functional end-stage macrophages which displayed a normal phenotypic profile. Upon viral challenge, the anti-HIV iPSC-derived macrophages exhibited strong protection from HIV-1 infection. Here, we demonstrate the ability of iPSCs to develop into HIV-1 resistant immune cells and highlight the potential use of iPSCs for HIV gene and cellular therapies.     

Duplex in the assessment of the free radial forearm flaps: Is it time to change practice?

Radial forearm free flaps (RFFFs) are safe, but critical ischaemia of the hand has been described and is catastrophic. Every effort should therefore be made to improve the safety margin even further. Colour flow duplex ultrasound (US) is a simple, non-invasive and effective assessment tool. We compared it with Allen's test to identify serious vascular anomalies. We studied 121 patients who were listed to have a RFFF harvested, all of whom had both duplex US assessment and Allen's testing of the selected arm. The significance of differences in proportions was assessed using McNemar's test. Five of the 121 patients had an alternative flap selected as a consequence of the duplex assessment. A single flap failed. There were no ischaemic vascular complications that affected the hand.