Anuran Heart Metamorphosis: Anatomical Support for Pulmonary Blood Separation in the Early Aquatic Phase

Background: In both larval and adult anurans, blood separation and respiratory physiology have remained an enigma. While various blood separation mechanisms have been proposed, the same structure is seen as playing a key role: the conus arteriosus. However, previous findings on its internal structure are contradictory, depending on the specifics of the 2D imaging methods used by different authors. To resolve this problem, we used high-resolution X-ray microtomography of whole Bufo bufo specimens to acquire the first detailed 3D descriptions of this complex structure through metamorphosis. Results: In early tadpoles two small valvular openings develop at the ventricular-conal junction, providing two paths separated by the septum coni and continuing into the aortic arches. Thus, structures to support segregated pulmonary circulation are fully developed well before the lungs appear. The external gills undergo partial resorption and retreat asymmetrically into a gill chamber formed by a hyoidal cover, leaving only a single opening on the left side, the opercular spout. Conclusions: The timing of events in Bufo circulatory development does not track the changing modes of respiration used by the developing tadpole. In particular, a system capable of double circulation carries only oxygen-depleted blood for a significant portion of the tadpole stage.

A dicephalus calf: anatomical, pathological and radiographic aspects

Congenital malformations are morphofunctional abnormalities of tissues and organs that can occur during embryonic or fetal development in all animal species. Among these, dicephalus is characterized by the development of an individual with two heads and two necks, due to the total duplication of facial, cranial, and brain structures. Reports of dicephalus in cattle are scarce and do not normally emphasize radiographic and bone anatomy characteristics. The objective was to describe a case of a stillborn dicephalus calf. The duplication of the head, brain, neck, and two thoracic vertebral columns, isolated from each other, with 13 vertebrae each was verified radiographically. There were 13 pairs of ribs, the ones on the right side articulated with the thoracic spine on the right and the left ones with the spine on the left. Caudally at T13, there was only one lumbar spine, sacral and coccygeal. In the ventrodorsal projection, L1, L2, L3, and L6 had the shape of a butterfly (suggestive of hemivertebrae). At necropsy, in addition to craniocervical and spinal morphological changes, collapsed lungs, duplication of the heart with anastomosis between the aortic arches of the hearts, and duplication of the upper digestive tract were observed. Additionally, there was arthrogryposis of the pelvic limbs. Corpse maceration, followed by the skeletal assembly, showed the bone changes previously observed and confirmed the suspicion of hemivertebrae.

Implications of different definitions for aortic arch classification provided by contemporary guidelines on thoracic aortic repair

Contemporary guidelines on thoracic aortic repair provide inconsistent reporting standards for the definition of aortic arch classification in Types I, II and III. The different reported criteria cannot be used interchangeably, due to a very low level of concordance, and this finding has relevant implications for the comparisons between studies using different classifications, and between different datasets of multicentre trials, which are not consistently analyzed with the same criteria. Also, the reported definitions, which were originally proposed for predicting difficult carotid stenting and therefore were conceived for healthy aortic arches, can be influenced by the pathological derangements of the aortic wall, including aneurysms and dissections. In this respect, the Madhwal’s classification, which is based on the diameter of the left common carotid artery, appears to be the more suitable one for aortic arch classification in patients with thoracic aortic disease because it provides relevant clinical information along with an adequate reproducibility.

KẾT QUẢ DÀI HẠN PHẪU THUẬT CẦU NỐI ĐỘNG MẠCH CHỦ NGỰC - ĐỘNG MẠCH CẢNH - DƯỚI ĐÒN

Objectives: The complex stenosis of the branches of the aortic arch is rare, it was the challenge for vascular surgeon to manage. The purpose of thisstudy was review our experience with diagnosis and surgical treatment for complex stenosis of the branches of the aortic arch .Methods: Prospective. Eveluate the clinical characteristics of complex stenosis of the branches of the aortic arches. Diagnosis was based on Dupplex scanning, MSCT and angiography. Intrathoracic bypass was indicated for all cases. Results: From 10/1999 to 10/2011, twelve patients with complex stenosis of the branches of the aortic arch were treated in Choray hospital and Thong nhat hospital. 4 cases stenosis of the carotid and the subclavian artery; 4 cases have stenosis the branchiocephalic artery; and 4had stenosis all of the branches of the aortic arch. 10 cases admission because of chronic upper extremity ischemia. 12 cases had TIA. Takayashu’s disease affected in 6 cases, atherosclerosis was the cause of 6 patients. All patients were diagnosed by Duplex scan, MSCT and arteriography. 2 cases with 99 percent stenosis, the others were completely occluded.Upper partial sternotomy were performed in all cases.; Aorto carotido-subclavian bypass in 7 cases; Aorto bi-carotid bi-subclavian bypass were performed in 4 cases; Branchiocephalo carotid and subclavian bypass in 1 case, PTFE prothesis graft was used in 2 cases. Dacron prothesis was used in the rest .No procedure-related mortality was observed. No stroke. There are 1 wound infection, No restenosis after 12 years follow up.Conclusions: Upper partial sternotomy is a very good approach for ascending aorto carotidosubclavian bypass operation. Ascending aorto carotido subclavian bypass should be done for stenosis of multi-branches.

2D versus 3D real time ultrasound with live xPlane imaging to visualize aortic and ductal arches: comparison between methods

Background The diagnosis of congenital heart defects is challenging, especially for what concerns conotruncal anomalies. Indeed, although the screening techniques of fetal cardiac anomalies have greatly improved, the detection rate of conotruncal anomalies still remains low due to the fact that they are associated with a normal four-chamber view. Therefore, the study aimed to compare real-time three-dimensional echocardiography with live xPlane imaging with two-dimensional (2D) traditional imaging in visualizing ductal and aortic arches during routine echocardiography of the second trimester of gestation. Methods This was an observational prospective study including 114 women with uncomplicated, singleton pregnancies. All sonographic studies were performed by two different operators, of them 60 by a first level operator, while 54 by a second level operator. A subanalysis was run in order to evaluate the feasibility and the time needed for the two procedures according to fetal spine position and operator’s experience. Results The measurements with 2D ultrasound were performed in all 114 echocardiographies, while live xPlane imaging was feasible in the 78% of the cases, and this was mainly due to fetal position. The time lapse needed to visualize aortic and ductal arches was significantly lower when using 2D ultrasound compared to live xPlane imaging (29.56 ± 28.5 s vs. 42.5 ± 38.1 s, P = 0.006 for aortic arch; 22.14 ± 17.8 s vs. 37.1 ± 33.8 s, P = 0.001 for ductal arch), also when performing a subanalysis according to operators’ experience (P < 0.05 for all comparisons). Feasibility of live xPlane proved to be correlated with the position of the fetal spine and the operator’s experience. Discussion To find a reproducible and standardized method to detect fetal heart defects may bring a great benefit for both patients and operators. In this scenario live xPlane imaging is a novel method to visualize ductal and aortic arches. We found that the position of the fetal spine may affect the feasibility of the method since, when the fetal back is anterior or transverse, the visualization of the correct view of three-vessels and trachea in order to set the reference line properly becomes more challenging. In addition, the fetal spine position influences the duration of the ultrasound examination. Regarding operator’s skills and experience, in our study a first level operator was able to perform the complete 2D and xPlane examination in a lower number of cases compared to second level operators. In addition, the time required for the complete examination was higher for first level operators. This means that this technique is based on an adequate operators’ expertise.

A tissue-specific, Gata6-driven transcriptional program instructs remodeling of the mature arterial tree

Connection of the heart to the systemic circulation is a critical developmental event that requires selective preservation of embryonic vessels (aortic arches). However, why some aortic arches regress while others are incorporated into the mature aortic tree remains unclear. By microdissection and deep sequencing in mouse, we find that neural crest (NC) only differentiates into vascular smooth muscle cells (SMCs) around those aortic arches destined for survival and reorganization, and identify the transcription factor Gata6 as a crucial regulator of this process. Gata6 is expressed in SMCs and its target genes activation control SMC differentiation. Furthermore, Gata6 is sufficient to promote SMCs differentiation in vivo, and drive preservation of aortic arches that ought to regress. These findings identify Gata6-directed differentiation of NC to SMCs as an essential mechanism that specifies the aortic tree, and provide a new framework for how mutations in GATA6 lead to congenital heart disorders in humans.