Negative Thermal Expansion in the Plateau State of a Magnetically Frustrated Spinel

We report on negative thermal expansion (NTE) in the high-field, half-magnetization plateau phase of the frustrated magnetic insulator CdCr_{2}O_{4}. Using dilatometry, we precisely map the phase diagram at fields of up to 30 T and identify a strong NTE associated with the collinear half-magnetization plateau for B>27  T. The resulting phase diagram is compared with a microscopic theory for spin-lattice coupling, and the origin of the NTE is identified as a large negative change in magnetization with temperature, coming from a nearly localized band of spin excitations in the plateau phase. These results provide useful guidelines for the discovery of new NTE materials.

A rare case of fetal extensive intracranial hemorrhage and whole-cerebral hypoplasia due to latent maternal vitamin K deficiency

We present here a late preterm infant with extensive brain lesions resulting from vitamin K deficiency. A female infant was born after 35 weeks of gestation by emergent cesarean section because of non-reassuring fetal status. Her mother had severe eating disorder and recurrent vomiting since early pregnancy. She was immediately intubated and ventilated because she was extremely pale, hypotonic, and non-reactive. Cerebral magnetic resonance imaging immediately after birth showed intraparenchymal hemorrhage in the left frontal lobe and cerebellum, marked cerebral edema, and cerebellar hypoplasia. Coagulation studies of the infant showed hepaplastin test <5%, prolonged PT and APTT, and a marked elevation of protein induced by vitamin K absence or antagonist-II. This case highlighted a potential risk of intracranial bleeding due to maternal vitamin K deficiency and difficulty in its prediction before delivery. Vitamin K supplementation to high risk mothers might be indispensable for preventing severe fetal vitamin K deficiency. Even when coagulation studies in mothers is normal, it is imperative to provide vitamin K supplementation for total protection.

Left Ventricular Aneurysm After Post-Infarction Ventricular Septal Defect Repair

The surgical indication and optimal approach for ischemic mitral regurgitation with ventricular septal defect remain uncertain. Very few studies have reported the occurrence of left ventricular aneurysms after repair of ischemic ventricular septal defects. We report a case of a left posterior ventricular aneurysm that developed after an urgent operation to repair an acute ischemic posterior ventricular septal defect using the double-patch sandwich technique via a right ventriculotomy.

Regeneration of the Junctional Epithelium and Connective Tissue after Transplantation of Detergent-Processed Allo-Teeth

The authors have developed a new artificial dental implant and evaluated it in a dog model in terms of its potential to produce: I) regeneration of junctional epithelium; II) regeneration and attachment of connective tissue. The implants were constructed from allo-teeth. We removed the cell components from the periodontal ligaments of these teeth with a detergent (1% TritonX-100); the remaining acellular periodontal ligament acted as an extracellular matrix upon which regeneration and attachment could proceed. We placed 10 of these implants in the just-extracted sites of three beagle dogs. We observed regeneration of both junctional epithelium and connective tissue at all implant sites after 3 months. The connective tissue was attached in all cases. Use of the acellular periodontal ligament as an extracellular matrix may facilitate regeneration of host periodontal ligament tissue, thus contributing to recovery of host immunological defense and long-term oral function.

Artificial Trachea and Long Term follow-up in Carinal Reconstruction in Dogs

We have already reported “del” successful carinal reconstruction of the trachea with an observation period of 1 – 2 years. In this study, we evaluate the long-term safety and efficacy of the reconstruction after 5-years of follow-up.

The Y-shaped Marlex® mesh tube was reinforced with a polypropylene spiral and coated with atelocollagen made from porcine skin. The prosthesis was 60 mm long with an outer diameter of 18 mm. Replacement of the tracheobronchial bifurcation was preformed through a right thoracotomy in a beagle dog. Bronchoscopical examination and sampling of the tracheal epithelium was performed periodically to check the function of cilia.

The implanted prothesis was promptly infiltrated by the surrounding connective tissue and completely incorporated by the host trachea and bronchus. Bronchoscopically, sufficient epithelization was confirmed from the upper to the lower site of anastomosis. After 5 years neither stenosis nor dehiscence was observed. In spite of there being mesh-exposure at the luminal surface, the dog had no clinical symptoms until sacrifice for pathological examination. The bent frequency of the cilia was maintained within the normal range, indicating “del” functional recovery of the regenerating airway.

Our tracheal prosthesis is promising for clinical “del” repair of the tracheobronchial bifurcation.

Right Subclavian Artery Aneurysms with Fibromuscular Dysplasia

Subclavian artery aneurysms (SAAs) are rare and even more uncommon in patients with fibromuscular dysplasia (FMD). A 20-year-old man with a past medical history of moyamoya disease presented with an abnormal mass shadow in the apex of the right lung on chest X-ray. Based on computed tomography imaging, a diagnosis of right SAA was established, and an excision of the aneurysm was performed. Because the left vertebral artery is dominant, the proximal and distal right subclavian artery and right vertebral artery were clamped. Then, the aneurysm was excised, and resection anastomosis was performed. Histological findings revealed FMD. The postsurgical course has been uneventful after 2 years. Among treatment modalities, open surgery would be the first choice for SAAs with FMD, despite the current era of endovascular surgeries.

Does the presence of coronary artery disease affect the outcome of aortic valve replacement?

The purpose of this study is to compare the late outcome of aortic valve replacement with or without preoperative coronary artery disease, and with or without coronary artery bypass. Between 2014 and 2015, 291 patients underwent aortic valve replacement. Average follow-up term was 2.5 ± 2.2 years. The retrospective comparative study was performed between the patients with (n = 115) or without (n = 176) preoperative coronary artery disease (Study 1) and with (n = 93) or without (n = 198) coronary artery bypass grafting (Study 2). Study 1: male patients were more, and diabetes was more in the patients with coronary artery disease. Long-term survival rate was significantly low in the patients with coronary artery disease (p = 0.0002 by log rank test). Freedom from repeat coronary revascularization rate was lower in the patients with coronary artery disease (p = 0.02 by log rank test). Study 2: operation time (419 ± 130 vs 290 ± 101; p = 0.0001) was longer in the patients with coronary artery bypass grafting. Improvement of ejection fraction at follow-up was more in the patients with coronary artery bypass(114 ± 43 vs 104 ± 26%; p = 0.03). Long-term survival rate and freedom from major adverse cardiac event rater were not different with or without coronary artery bypass grafting (p = 0.26 and p = 0.59, respectively, by log rank test). Although prevalence of coronary artery disease inversely affected the long-term outcome of the aortic valve replacement, simultaneous coronary artery bypass did not. Aggressive simultaneous coronary revascularization would be important to improve the long-term outcome of aortic valve replacement.

Surgical management of nonbacterial thrombotic endocarditis in malignancy

Background

Nonbacterial thrombotic endocarditis is commonly seen on heart valves in patients with malignant or collagen diseases. The natural prognosis of nonbacterial thrombotic endocarditis is reported to be poor due to underlying malignancy. Surgical indications and appropriate timing for surgery for nonbacterial thrombotic endocarditis and underlying malignancy have not been formally studied.

Case presentation

The case was a 45-year-old woman who presented with a history of systemic embolization associated with occult malignancy. A preoperative transesophageal echocardiogram showed multiple mobile vegetations on the aortic and mitral valves. She underwent valve surgery to prevent recurrent embolization. Based on the histopathologic findings, she was diagnosed with nonbacterial thrombotic endocarditis. She subsequently underwent surgery for occult malignancy, which was diagnosed as endometrioid adenocarcinoma.

Conclusions

Although surgical indications for nonbacterial thrombotic endocarditis remain unclear, valve replacement or repair and multidisciplinary treatment including surgical intervention are essential to prevent recurrent embolization in patients with nonbacterial thrombotic endocarditis associated with malignancy.

The behavioural homing response of adult chum salmon Oncorhynchus keta to amino-acid profiles

Adult chum salmon Oncorhynchus keta homing behaviour in a two-choice test tank (Y-maze) was monitored using a passive integrated transponder (PIT)-tag system in response to river-specific dissolved free amino-acid (DFAA) profiles and revealed that the majority of O. keta showed a preference for artificial natal-stream water and tended to stay in this maze arm for a longer period; natal-stream water was chosen over a nearby tributary's water, but not when the O. keta were presented with a non-tributary water. The results demonstrate the ability of O. keta to discriminate artificial stream waters containing natural levels of DFAA.

Long-term consequences of atrial fibrillation after aortic valve replacement

Background

Atrial fibrillation is a common complication after cardiac surgery, but the risk factors and long-term outcome after primary isolated aortic valve replacement remains to be clarified.

Methods

A single-center retrospective study was conducted on 157 patients who underwent first-time isolated aortic valve replacement between April 1999 and February 2015. Fifty-eight patients developed new-onset atrial fibrillation within 6 months postoperatively, and they were compared with patients who remained in sinus rhythm. Multivariate analyses, which incorporated the propensity score patient matching technique, were conducted to evaluate the long-term outcome of new-onset postoperative atrial fibrillation and identify patients at risk of developing this arrhythmia.

Results

At a mean follow-up of 52.4 months (range 8.4–200.7 months), mortality was significantly higher in patients who developed atrial fibrillation compared to those who remained in sinus rhythm (2.8%/patient-year vs. 0.2%/patient-year, respectively; p < 0.05). Patients developing atrial fibrillation were also at an independently increased risk of stroke and readmission during follow-up. Risk analysis revealed that advanced age (>70 years) and absence of a postoperative β-blocker were predictors of atrial fibrillation.

Conclusions

New-onset atrial fibrillation after first-time isolated aortic valve replacement correlated significantly with late morbidity and mortality. Advanced age and absence of a postoperative β-blocker may increase the incidence of atrial fibrillation.

Enlargement of aortic arch vessels after surgical repair of type A aortic dissection

BACKGROUND

Information on the growth rate of the diameter of the residual dissected supra-aortic trunk after surgical repair of type A aortic dissection is limited.

METHODS

We retrospectively reviewed 95 consecutive postsurgical patients with type A aortic dissection (acute, 91; chronic, 4) between 2005 and 2016 who were followed up with computed tomography. The diameter of the residual dissected supra-aortic trunk was measured by axial images and multiplanar reformatting, and the growth rate was calculated.

RESULTS

The mean age was 67.2 ± 12.8 years (range, 34-89 years). Forty-one brachiocephalic arteries (43%), 14 left common carotid arteries (15%), and 7 left subclavian arteries (10%) exhibited residual dissection. The diameter of the residual dissected branch with a patent false lumen (FL) gradually increased over time, whereas that with a thrombosed FL decreased and reached a plateau. The growth rate of brachiocephalic, left common carotid, and left subclavian arteries with a patent FL was 1.3 ± 1.2, 0.8 ± 0.3, and 0.6 ± 0.4 mm/y, respectively. One patient required surgical intervention for dilation of the brachiocephalic artery 8 years postoperatively. Multivariate analysis showed that male sex was an independent risk factor for a patent FL in the brachiocephalic artery (P = .0431; odds ratio, 2.04).

CONCLUSIONS

A residual dissected supra-aortic trunk with a thrombosed FL seems to be a benign condition. However, long-term follow-up is necessary for patients with a patent FL of residual dissected supra-aortic trunk, which might occasionally require surgical intervention.