Analyses of circRNA Expression throughout the Light-Dark Cycle Reveal a Strong Regulation of Cdr1as,Associated with Light Entrainment in the SCN

Circular RNAs (circRNAs) are a large class of relatively stable RNA molecules that are highly expressed in animal brains. Many circRNAs have been associated with CNS disorders accompanied by an aberrant wake-sleep cycle. However, the regulation of circRNAs in brain homeostasis over daily light-dark (LD) cycles has not been characterized. Here, we aim to quantify the daily expression changes of circRNAs in physiological conditions in healthy adult animals. Using newly generated and public RNA-Seq data, we monitored circRNA expression throughout the 12:12 h LD cycle in various mouse brain regions. We identified that Cdr1as, a conserved circRNA that regulates synaptic transmission, is highly expressed in the suprachiasmatic nucleus (SCN), the master circadian pacemaker. Despite its high stability, Cdr1as has a very dynamic expression in the SCN throughout the LD cycle, as well as a significant regulation in the hippocampus following the entry into the dark phase. Computational integration of different public datasets predicted that Cdr1as is important for regulating light entrainment in the SCN. We hypothesize that the expression changes of Cdr1as in the SCN, particularly during the dark phase, are associated with light-induced phase shifts. Importantly, our work revises the current beliefs about natural circRNA stability and suggests that the time component must be considered when studying circRNA regulation.     

Bacterial wound colonization after broad-spectrum versus narrow-spectrum antibiotics

Broad-spectrum versus narrow-spectrum antibiotic prophylaxis for patients who undergo cardiac operations is variously advocated to reduce the incidence of all infections or, conversely, to prevent resistant superinfections. Previous studies of prophylaxis have shown a reduction in the incidence of staphylococcal infections with some increased resistance. We studied preoperative and postoperative wound colonization as a surrogate for infection. Among 78 patients undergoing cardiac procedures, the type of prophylaxis was allocated as follows: narrow-spectrum (nafcillin), 24 patients; midspectrum (cephapirin), 26 patients; and broad-spectrum (ceftriaxone), 28 patients. Seventeen patients who underwent other procedures received no antibiotics and served as controls. Cultures of the operative site were done preoperatively, and 3 and 6 days postoperatively. The incidence of preoperative skin colonization with staphylococci was identical (95%) in all groups. Postoperatively, more patients receiving nafcillin (48%) were culture-negative for all organisms than were either of the other groups receiving antibiotics (27% and 22%) (p < 0.05). Gram-negative bacilli were infrequent colonizers and neither did the incidence of infection with these organisms increase nor did resistance develop in any group. The infection rates were not different among the treatment groups. Thus, a narrow-spectrum antistaphylococcal penicillin may offer an advantage in terms of both prophylaxis for cardiac operations and hospital costs.     

DNA‐Binding Properties of New Fluorescent AzaHx Amides: Methoxypyridylazabenzimidazolepyrroleimidazole/pyrrole

DNA minor groove binding polyamides have been extensively developed to control abnormal gene expression. The establishment of novel, inherently fluorescent 2‐(p‐anisyl)benzimidazole (Hx) amides has provided an alternative path for studying DNA binding in cells by direct observation of cell localization. Because of the 2:1 antiparallel stacking homodimer binding mode of these molecules to DNA, modification of Hx amides to 2‐(p‐anisyl)‐4‐azabenzimidazole (AzaHx) amides has successfully extended the DNA‐recognition repertoire from central CG [recognized by Hx‐I (I=N‐methylimidazole)] to central GC [recognized by AzaHx‐P (P=N‐methylpyrrole)] recognition. For potential targeting of two consecutive GG bases, modification of the AzaHx moiety to 2‐ and 3‐pyridyl‐aza‐benzimidazole (Pyr‐AzaHx) moieties was explored. The newly designed molecules are also small‐sized, fluorescent amides with the Pyr‐AzaHx moiety connected to two conventional five‐membered heterocycles. Complementary biophysical methods were performed to investigate the DNA‐binding properties of these molecules. The results showed that neither 3‐Pyr‐AzaHx nor 2‐Pyr‐AzaHx was able to mimic I‐I=N‐methylimidazole–N‐methylimidazole to target GG dinucleotides specifically. Rather, 3‐Pyr‐AzaHx was found to function like AzaHx, f‐I (f=formamide), or P‐I as an antiparallel stacked dimer. 3‐Pyr‐AzaHx‐PI ( 2 ) binds 5′‐ACGCGT′‐3′ with improved binding affinity and high sequence specificity in comparison to its parent molecule AzaHx‐PI ( 1 ). However, 2‐Pyr‐AzaHx is detrimental to DNA binding because of an unfavorable steric clash upon stacking in the minor groove.     

Paths of influence of divorce on preschool children's psychosocial adjustment.

This study examined the direct and indirect influences of parental divorce on preschool children's psychosocial adjustment through its effect on maternal strain, family socioeconomic status, the quality of the family's interpersonal relationships, and mother–child interaction. Participants included 198 married (n?=?99) and divorced (n?=?99), predominantly White, lower- to middle-income families with preschool children. Analyses using structural equation modeling (SEM) indicate that family structure and processes in combination most strongly influenced child outcomes. Specifically, the effects of divorce on children's adjustment were mediated by maternal strain and the quality of mother–child interaction. The goodness-of-fit indices (.90 to .94), root mean square error of approximation index (.03), and nonsignificant chi-square (p?=?.12) indicated a good fit for the generated structural equation model. (PsycINFO Database Record (c) 2010 APA, all rights reserved)