**Author details**

Eduardo Félix Martins Santana1,2\*, Vivian Melo Corrêa1 , Isabela Bottura2 and José Pedro Parise Filho2

\*Address all correspondence to<EMAIL_ADDRESS>
1 Department of Obstetrics, Paulista School of Medicine, Federal University of São Paulo (EPM-UNIFESP), São Paulo, SP, Brazil

2 Department of Perinatology, Albert Einstein Hospital, São Paulo, SP, Brazil


**4. Biogenesis of non-coding RNA**

Basically, ncRNAs are consequence of various processes, such as the process of duplication, modification of transposons during the evolutionary process, pseudogenization of actual coding sequences, doubling of RNA viruses, part of some hairpin structures, double-stranded RNAs from heterochromatin regions and DNA repeats [19]. Despite having a similar structural build, the sRNA varies greatly in their method of biogenesis.

*Non-Coding RNA and Its Prospective Utilization in Plant Breeding DOI: http://dx.doi.org/10.5772/intechopen.106429*

> **Table 3.** *Brief details about the ncRNA classification.*

#### **4.1 miRNA**

MicroRNAs are generated out of primary microRNAs (pri-miRNAs) by the action of RNA polymerase II. These precursor molecules have a double-stranded secondary structure which later on gets cleaved by DICER-LIKE 1 (DCL1) molecules to form single-stranded siRNA. These raw miRNAs is further processed in the nucleus before being exported to the cytoplasm [1]. Mature single miRNA that incorporates the RISC complex binds with other complementary mRNA sequences [20].

#### **4.2 IsomiRNAs**

IsomiRNAs (IsomiRNAs) are one of the variants of miRNAs that arise because of the inaccurate cleavage action performed through the RNase III enzyme. These may also be developed via the process of post-transcriptional RNA editing [21, 22].

### **4.3 siRNA**

siRNAs are derived from long dsRNAs produced during varied mechanisms, such as folding in an inverted sequence, from a long non-coding RNA, hybridization of two fully or partially complementary sequences *.* This further gets processed by the action of DCL2, DCL3, and DCL 4 proteins, leading to the formation of 22 nt, 24 nt, and 21 nt siRNA, respectively [3]. RNA-dependent RNA polymerases 2 and 6 (RDR2, RDR6), and DNA-dependent RNA polymerases IV and V in plants also take part in the production of siRNAs [23].

### **4.4 phasiRNA and tasiRNA**

In plants, phasiRNAs are the partially degraded product of mRNA as being passed through the RISC complex. DCL proteins are involved in this slicing process of dsRNAs to form a group of 21- or 24-nt siRNAs, termed phasiRNAs, *Trans*-acting siRNAs (tasiRNAs) are a class of DCL4-dependent 21-nt phasiRNAs generated from non-coding *TAS* transcripts [24, 25].

#### **4.5 lncRNA**

lncRNAs have appeared from intergenic, particularly regions giving rise to long intergenic ncRNAs (lincRNAs) and those developed from intronic regions giving intronic ncRNAs (incRNAs) [26]. lincRNAs and IncRNAs belong to conventional linear lncRNAs. Circular RNAs (circRNAs) generally develop from coding regions or intronic regions.

#### *4.5.1 Linear-long non-coding RNAs*

The lncRNAs, such as lincRNAs and IncRNAs are linear lncRNAs transcribed by Pol II. Because of having similar features as that of mRNA with a 5\_ m7G cap and a 3\_ poly (A) tail, they undergo similar modifications later on called mRNA mimics [27].


**2. Risk factors for GIC-CTS**

Numerous studies report on specific risk factors for GIC-CTS. Although some of the factors seem to be universally present across different studies, some others are likely unique to spe‐ cific study populations. A comprehensive list of commonly cited risk factors compiled from the literature includes: (a) decreased left ventricular ejection fraction (<40%) including post‐ operative low cardiac output; (b) advanced patient age; (c) pre-existing conditions such as diabetes, renal failure, peripheral vascular disease; (d) valvular surgery or combined coro‐

© 2013 Schwartz et al.; licensee InTech. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. © 2013 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

nary artery bypass/valve operation; (e) prolonged mechanical ventilation; (f) emergency sur‐ gery; (g) prolonged pump time; (h) need for intra-aortic balloon pump (IABP) or vasopressors during or after surgery; (i) need for re-exploration following surgery (re-ster‐ notomy or re-thoracotomy); (j) pre-existing gastric ulcer disease; (k) stroke; and (l) postoper‐ ative sepsis/infectious complications including sternal wound infection [3-5, 9-12].

such as mesenteric ischemia or pancreatitis [15]. Mandatory perioperative fasting, the effect of anesthetic agents, and decreased patient mobility during immediate postoperative recov‐ ery, all contribute to temporary intestinal dysfunction, which in the vast majority of cases regresses automatically after the initiation of enteral intake. In a small proportion of patients the ileus persists past the fourth postoperative day, requiring the use of suppositories, ene‐ mas, and pro-motility agents (i.e., metaclopramide, erythromycin) to facilitate clinical reso‐ lution [17, 18]. In addition, the use of opioids has to be minimized due to the inhibitory effect of these analgesic agents on bowel motility [19]. The abovementioned measures, in conjunction with close clinical monitoring and normalization of serum electrolyte concentra‐ tions, are usually successful in restoring or improving intestinal function [20]. Cases that re‐ main unresponsive are treated with a course of nasogastric suction, which should be

Gastrointestinal Complications in Cardiothoracic Surgery: A Synopsis

http://dx.doi.org/10.5772/54348

357

Colonic pseudo-obstruction is a rare, poorly understood surgical complication with multifac‐ torial origins [21]. Characterized by marked colonic distention in the absence of distal obstruc‐ tion (Figure 2), this condition seems to be associated with the disturbance of the autonomic innervation of the colon [22]. Untreated, colonic pseudo-obstruction leads to cecal over-disten‐ tion and subsequent perforation, with reported mortality as high as 15-50% [21, 22]. The critical cecal diameter range at which perforation is more likely to occur is between 9-12 centimeters [23]. The two main management modalities for colonic pseudo-obstruction, used alone or in combination, are neostigmine administration and colonoscopic decompression [22, 24]. De‐ pending on whether indicated by the finding of bowel perforation or repeated episodes of pseudo-obstruction, surgical options vary from cecal decompression (i.e., cecostomy) to colon‐ ic resection with entero-enterostomy or ostomy creation [25]. In the presence of sepsis with he‐

Dysphagia is a common complaint following cardio-thoracic operations [29]. Undoubtedly, there is an association between history of endotracheal intubation, median sternotomy or thoracotomy incisions, postoperative inflammatory changes in the chest/mediastinum and dysphagia in the CTS patient population. The etiology of postoperative dysphagia is multi‐ factorial, including contributions from gastroesophageal reflux, local tissue trauma from surgery and endotracheal intubation, intraoperative trans-esophageal echocardiography (TEE), and other potential factors such as recurrent/superior laryngeal nerve dysfunction or injury [30]. One of the more interesting contributors to post-CTS dysphagia is the perform‐ ance of intraoperative TEE, with nearly 8 times greater odds of developing dysphagia

modynamic instability, damage control surgery may be justified [26-28].

among patients who underwent TEE versus those who did not [31].

continued until the return of bowel function.

**4. Colonic pseudo-obstruction**

**5. Dysphagia**