The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu.

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Background White matter (WM) injury is common after neonatal cardiopulmonary bypass (CPB). We have demonstrated that the inflammatory response to CPB is an important mechanism of WM injury. Microglia are brain-specific immune cells that respond to inflammation and can exacerbate injury. We hypothesized that microglia activation contributes to WM injury caused by CPB. Methods Juvenile piglets were randomly assigned to one of three CPB-induced brain insults (1: no-CPB, 2: full-flow CPB, 3: CPB/Circulatory-arrest). Neurobehavioral tests were performed. Animals were sacrificed 3-days or 4-weeks post-operatively. Microglia and proliferating cells were immunohistologically identified. Seven analyzed WM regions were further categorized into 3-fiber connections (1: Commissural, 2: Projection, 3: Association fibers). Results Microglia numbers significantly increased on day 3 after CPB/Circulatory-arrest, but not after full-flow CPB. Fiber categories did not affect these changes. On post-CPB week 4, proliferating cell number, blood leukocyte number and IL-6 levels, and neurological scores had normalized. However, both full-flow CPB and CPB/Circulatory-arrest displayed significant increases in the microglia number compared with Control. Thus brain-specific inflammation after CPB persists despite no changes in systemic biomarkers. Microglia number was significantly different among fiber categories, being highest in Association and lowest in Commissural connections. Thus there was a WM fiber-dependent microglia reaction to CPB. Conclusions This study demonstrates prolonged microglia activation in WM after CPB. This brain-specific inflammatory response is systemically silent. It is connection fiber-dependent which may impact specific connectivity deficits observed after CPB. Controlling microglia activation after CPB is a potential therapeutic intervention to limit neurological deficits following CPB.

BackgroundNewly developed white matter (WM) injury is common after cardiopulmonary bypass (CPB) in severe/complex congenital heart disease. Fractional anisotropy (FA) allows measurement of macroscopic organization of WM pathology but has rarely been applied after CPB. The aims of our animal study were to define CPB‐induced FA alterations and to determine correlations between these changes and cellular events after congenital heart disease surgery.Methods and ResultsNormal porcine WM development was first assessed between 3 and 7 weeks of age: 3‐week‐old piglets were randomly assigned to 1 of 3 CPB‐induced insults. FA was analyzed in 31 WM structures. WM oligodendrocytes, astrocytes, and microglia were assessed immunohistologically. Normal porcine WM development resembles human WM development in early infancy. We found region‐specific WM vulnerability to insults associated with CPB. FA changes after CPB were also insult dependent. Within various WM areas, WM within the frontal cortex was susceptible, suggesting that FA in the frontal cortex should be a biomarker for WM injury after CPB. FA increases occur parallel to cellular processes of WM maturation during normal development; however, they are altered following surgery. CPB‐induced oligodendrocyte dysmaturation, astrogliosis, and microglial expansion affect these changes. FA enabled capturing CPB‐induced cellular events 4 weeks postoperatively. Regions most resilient to CPB‐induced FA reduction were those that maintained mature oligodendrocytes.ConclusionsReducing alterations of oligodendrocyte development in the frontal cortex can be both a metric and a goal to improve neurodevelopmental impairment in the congenital heart disease population. Studies using this model can provide important data needed to better interpret human imaging studies.

Atherosclerotic cardiovascular disease (ASCVD) remains the leading cause of mortality in women. Historically, medical research has focused on male patients, and subsequently, there has been decreased awareness of the burden of ASCVD in females until recent years. The biological differences between sexes and differences in societal expectations defined by gender roles contribute to gender differences in ASCVD risk factors. With these differing risk profiles, risk assessment, risk stratification, and primary preventive measures of ASCVD are different in women and men. In this review article, clinicians will understand the risk factors unique to women, such as preeclampsia, gestational diabetes, and those that disproportionately affect them such as autoimmune disorders. With these conditions in mind, the approach to ASCVD risk assessment and stratification in women will be discussed. Furthermore, the literature behind the effects of primary preventive measures in women, including lifestyle modifications, aspirin, statins, and anticoagulation, will be reviewed. The aim of this review article was to ultimately improve ASCVD primary prevention by reducing gender disparities through education of physicians.