The Constrained Maximal Expression Level Owing to Haploidy Shapes Gene Content on the Mammalian X Chromosome.

X chromosomes are unusual in many regards, not least of which is their nonrandom gene content. The causes of this bias are commonly discussed in the context of sexual antagonism and the avoidance of activity in the male germline. Here, we examine the notion that, at least in some taxa, functionally biased gene content may more profoundly be shaped by limits imposed on gene expression owing to haploid expression of the X chromosome. Notably, if the X, as in primates, is transcribed at rates comparable to the ancestral rate (per promoter) prior to the X chromosome formation, then the X is not a tolerable environment for genes with very high maximal net levels of expression, owing to transcriptional traffic jams. We test this hypothesis using The Encyclopedia of DNA Elements (ENCODE) and data from the Functional Annotation of the Mammalian Genome (FANTOM5) project. As predicted, the maximal expression of human X-linked genes is much lower than that of genes on autosomes: on average, maximal expression is three times lower on the X chromosome than on autosomes. Similarly, autosome-to-X retroposition events are associated with lower maximal expression of retrogenes on the X than seen for X-to-autosome retrogenes on autosomes. Also as expected, X-linked genes have a lesser degree of increase in gene expression than autosomal ones (compared to the human/Chimpanzee common ancestor) if highly expressed, but not if lowly expressed. The traffic jam model also explains the known lower breadth of expression for genes on the X (and the Z of birds), as genes with broad expression are, on average, those with high maximal expression. As then further predicted, highly expressed tissue-specific genes are also rare on the X and broadly expressed genes on the X tend to be lowly expressed, both indicating that the trend is shaped by the maximal expression level not the breadth of expression per se. Importantly, a limit to the maximal expression level explains biased tissue of expression profiles of X-linked genes. Tissues whose tissue-specific genes are very highly expressed (e.g., secretory tissues, tissues abundant in structural proteins) are also tissues in which gene expression is relatively rare on the X chromosome. These trends cannot be fully accounted for in terms of alternative models of biased expression. In conclusion, the notion that it is hard for genes on the Therian X to be highly expressed, owing to transcriptional traffic jams, provides a simple yet robustly supported rationale of many peculiar features of X's gene content, gene expression, and evolution

Effects of glucose-insulin infusion during major oral and maxillofacial surgery on postoperative complications and outcomes

Abstract Background Secretion of hormones, which antagonize the action of insulin, is facilitated in response to surgery, and acute resistance to the action of insulin develops. Our aim is to elucidate the effects of intraoperative glycemic control by glucose-insulin (GI) infusion on postoperative complications and outcomes in major oral and maxillofacial surgery. Findings Thirty patients aged ≥ 60 years undergoing a radical operation of oral malignant tumors with tissue reconstruction (≥ 8 h) were analyzed. In the GI group, regular insulin was continuously applied with glucose-added acetate Ringer’s solution (5–10 g glucose per 500 mL). Blood glucose was adjusted within the target concentration of 80–120 mg/dL. In the control group, combination of acetate Ringer’s solution containing 1% (W/V) glucose and lactate Ringer’s solution, which contains no glucose, was employed. Perioperative clinical parameters, incidence of hypoalbuminemia, and postoperative complications, i.e., surgical site infection, necrosis of a reconstructed flap, bacteremia, hypotension, or pneumonia, were compared. Both serum total protein and albumin concentrations (postoperative day 1 [Day1]) were higher in the GI group. The mean infusion rate of glucose during surgery (mg/kg/h) was independently associated with the decrease in both serum total protein and albumin concentrations from the control to Day1. No difference was found between the groups in the incidence of postoperative complications and the days required until discharge, except less incidence of hypoalbuminemia in the GI group. Conclusions Application of additional glucose during major oral and maxillofacial surgery preserved serum albumin concentration. However, it did not lead to less postoperative complications and less days until discharge

A morphological analysis of thalamocortical axon fibers of rat posterior thalamic nuclei: a single neuron tracing study with viral vectors.

The rostral sector of the posterior thalamic nuclei (POm) is, together with the ventral posterior nuclei (VP), involved in somatosensory information processing in rodents. The POm receives inputs from the spinal cord and trigeminal nuclei and projects to the primary somatosensory (S1) cortex and other cortical areas. Although thalamocortical axons of single VP neurons are well known to innervate layer (L) 4 of the S1 cortex with distinct columnar organization, those of POm neurons have not been elucidated yet. In the present study, we investigated complete axonal and dendritic arborizations of single POm neurons in rats by visualizing the processes with Sindbis viruses expressing membrane-targeted fluorescent protein. When we divided the POm into anterior and posterior parts according to calbindin immunoreactivity, dendrites of posterior POm neurons were wider but less numerous than those of anterior neurons. More interestingly, axon fibers of anterior POm neurons were preferentially distributed in L5 of the S1 cortex, whereas those of posterior neurons were principally spread in L1 with wider and sparser arborization than those of anterior neurons. These results suggest that the POm is functionally segregated into anterior and posterior parts and that the 2 parts may play different roles in somatosensory information processing

Tracking cells implanted into cynomolgus monkeys (<i>Macaca fascicularis</i>) using MRI

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