Aortic regurgitation in Marfan syndrome patients who underwent prophylactic surgery: A single-center experience.

BACKGROUND: Marfan syndrome is an inherited connective tissue disease that causes aortic root dilatation and dissection and requires surgical intervention. Apart from emergent surgery for aortic dissection or aortic aneurysmal rupture, prophylactic surgical intervention can also be administered, depending on the severity of aortic root dilatation. The direct relationship between surgical intervention and aortic regurgitation was seldom mentioned in previous studies. METHODS: A retrospective cohort study was designed to determine the clinical presentations of prophylactic surgery in patients with Marfan syndrome. Between January 2009 and May 2019, 112 patients, adolescents and young adults, treated in the Department of Pediatric Cardiology of Taipei Veterans General Hospital, were enrolled. All patients' sex, body measurements, echocardiography reports, and surgical notes were collected for statistical analysis. RESULTS: Among the participants, nine patients (8%) underwent the Bentall procedure, and the other 103 did not receive surgical intervention. The operation group had a larger aortic root size (4.89 vs 2.86 cm, p < 0.001), more dilated left ventricle (4.81 vs 4.1 cm, p = 0.002), and higher prevalence of moderate and severe aortic regurgitation (66% vs 1%, p < 0.001) than the nonoperation group. CONCLUSION: Among adolescents and young adults with Marfan syndrome, echocardiographic presentation of aortic root dilatation, left ventricular dilatation, and significant aortic regurgitation was significantly associated with prophylactic surgical intervention. According to the study, significant aortic regurgitation should also be considered as an important indication for prophylactic surgery.

Effects of Mo, Nb, Ta, Ti, and Zr on Mechanical Properties of Equiatomic Hf-Mo-Nb-Ta-Ti-Zr Alloys.

Nowadays refractory high-entropy alloys (RHEAs) are regarded as great candidates for the replacement of superalloys at high temperature. To design a RHEA, one must understand the pros and cons of every refractory element. However, the elemental effect on mechanical properties remains unclear. In this study, the subtraction method was applied on equiatomic HfMoNbTaTiZr alloys to discover the role of each element, and, thus, HfMoNbTaTiZr, HfNbTaTiZr, HfMoTaTiZr, HfMoNbTiZr, HfMoNbTaZr, and HfMoNbTaTi were fabricated and analyzed. The microstructure and mechanical properties of each alloy at the as-cast state were examined. The solid solution phase formation rule and the solution strengthening effect are also discussed. Finally, the mechanism of how Mo, Nb, Ta, Ti, and Zr affect the HfMoNbTaTiZr alloys was established after comparing the properties of these alloys.

Rapid and highly sensitive detection of Enterovirus 71 by using nanogold-enhanced electrochemical impedance spectroscopy.

Enterovirus 71 (EV71) infection is an emerging infectious disease causing neurological complications and/or death within two to three days after the development of fever and rash. A low viral titre in clinical specimens makes the detection of EV71 difficult. Conventional approaches for detecting EV71 are time consuming, poorly sensitive, or complicated, and cannot be used effectively for clinical diagnosis. Furthermore, EV71 and Coxsackie virus A16 (CA16) may cross react in conventional assays. Therefore, a rapid, highly sensitive, specific, and user-friendly test is needed. We developed an EV71-specific nanogold-modified working electrode for electrochemical impedance spectroscopy in the detection of EV71. Our results show that EV71 can be distinguished from CA16, Herpes simplex virus, and lysozyme, with the modified nanogold electrode being able to detect EV71 in concentrations as low as 1 copy number/50 µl reaction volume, and the duration between sample preparation and detection being 11 min. This detection platform may have the potential for use in point-of-care diagnostics.

Sn-doped In2O3 nanowires: enhancement of electrical field emission by a selective area growth.

Selective area growth of single crystalline Sn-doped In2O3 (ITO) nanowires synthesized via vapor-liquid-solid (VLS) method at 600°C was applied to improve the field emission behavior owing to the reduction of screen effect. The enhanced field emission performance reveals the reduction of turn-on fields from 9.3 to 6.6 V µm-1 with increase of field enhancement factors (ß) from 1,621 to 1,857 after the selective area growth at 3 h. Moreover, we find that the screen effect also highly depends on the length of nanowires on the field emission performance. Consequently, the turn-on fields increase from 6.6 to 13.6 V µm-1 with decreasing ß values from 1,857 to 699 after the 10-h growth. The detailed screen effect in terms of electrical potential and NW density are investigated in details. The findings provide an effective way of improving the field emission properties for nanodevice application.

Diagnostic application of multidetector-row computed tomographic coronary angiography to assess coronary abnormalities in pediatric patients: comparison with invasive coronary angiography.

BACKGROUND: Multidetector-row computed tomographic (MDCT) coronary angiography has been validated for noninvasive assessment of coronary anatomy. However, we have less experience in diagnosing children with congenital or acquired coronary artery abnormalities by MDCT. We compared the results of MDCT with invasive coronary angiography (ICA) on identifying coronary abnormalities in infants, children, and adolescents with coronary artery abnormalities, including aneurysm, coronary fistula, or anomalous left coronary artery from pulmonary artery (ALCAPA). METHODS: From January 2002 to December 2009, patients with congenital or acquired coronary abnormalities underwent either ICA, MDCT, or both studies for assessment of coronary anatomy. We reviewed all patients' clinical diagnosis, coronary abnormalities identified by MDCT or ICA, and analyzed the advantages and disadvantages between those two methods. RESULTS: Thirty-three patients (20 males and 13 females) with a mean age of 10.3 years (range: 18 days to 25 years) had coronary abnormalities, including coronary artery aneurysm in Kawasaki disease (n=15), coronary artery fistula (n=12), myocardial bridge (n=2), and ALCAPA (n=4). In 17 patients only referred for ICA, 5 coronary aneurysms (3 on left main coronary artery, 1 on left anterior descending artery segment proximal, 1 on right coronary artery segment proximal), 11 coronary artery fistulas, and 2 ALCAPAs were detected. Sixteen patients received MDCT study, and 14 coronary artery aneurysms (4 on right coronary artery, 5 on left main coronary artery, 4 on left anterior descending artery, 1 on left circumflex artery), 3 myocardial bridges, 1 coronary artery fistulas, and 2 ALCAPAs were assessed. Ten patients with Kawasaki disease-related coronary lesions received MDCT study, and totally 102 (78.5%) segments permitted visualization with accurate diagnostic image quality. In this study, there were 11 patients with indication for conventional ICA spared invasive angiography after precise assessment by MDCT. CONCLUSION: We conclude that MDCT is a good and useful modality for assessment of congenital or acquired coronary abnormalities in pediatric patients. However, MDCT cannot replace invasive cardiac catheterization and ICA because of lack of therapeutic role.

The clinical manifestations and risk factors of a delayed diagnosis of Kawasaki disease.

BACKGROUND: Kawasaki disease (KD) is an acute febrile vasculitis and may cause coronary artery abnormalities. Due to the higher incidence in Asian countries, most pediatricians in Taiwan are familiar with KD. However, there are still some patients being diagnosed 10 days after the onset of the illness and not receiving a highly effective therapy. In this study, we analyzed the risk factors and clinical manifestations of patients with a delayed diagnosis of KD. METHODS: A retrospective review was made of the medical records of the patients diagnosed with KD at our institution between January 1996 and December 2005. The patients were divided into 2 groups: early-diagnosis group (EDG: diagnosis was made within 10 days after the onset of the fever) and delayed-diagnosis group (DDG: diagnosis was made 10 days after the onset of the fever). RESULTS: Fourteen of a total of 78 children (17.9%) were grouped into the DDG group, and 64 into the EDG group. There were no statistical differences between the 2 groups in terms of age, gender, number of antibiotics used, day of the first medical visit, total days of skin rash, conjunctivitis, mucosa changes, lymphadenopathy or laboratory examinations except for the higher white blood cell count and serum immunoglobulin G level in the DDG group. The patients in the EDG group had a clustered onset of symptoms as compared to the DDG group with a dispersed and late onset of symptoms. There was a higher risk of coronary artery abnormalities in the DDG group than the EDG group (42.9% vs. 14.1%; p = 0.036), and in the patients with KD who were younger than 1 year (29.0% vs. 12.7%; p = 0.043). CONCLUSION: Patients with delayed diagnosis of KD were associated with higher risk of developing coronary arterial lesions. It is necessary to develop a diagnostic test for KD and provide more education to health care providers for early recognition of KD.

Assessment of left ventricular dysfunction in children undergoing chemotherapy.

BACKGROUND: In Taiwan, children with malignancies are treated under the protocols of the Taiwan Pediatric Oncology Group (TPOG). The purpose of this study was to determine the change in left ventricular (LV) function in pediatric patients undergoing chemotherapy. METHODS: A total of 19 pediatric patients (mean age, 12.5 +/- 4.6 years; 11 males, 8 females) were enrolled. We divided the patients into 2 groups: (1) osteogenic sarcoma (OGS) group (n = 12; Group I); and (2) non-osteogenic sarcoma (non-OGS) group (n = 7; Group II). The accumulated dosages of anthracycline in Group I and II patients were 144.3 +/- 56.4 mg/M2 and 131.7 +/- 105.5 mg/M2 (p = 0.735), respectively. The children received echocardiography to investigate the parameters of LV systolic function, LV diastolic function, and myocardial performance index (MPI) after the entire chemotherapy course. RESULTS: Higher E/A ratio (1.71 +/- 0.37), shorter isovolumic relaxation time (IRT, 42 +/- 19.14 ms), and shorter deceleration time (DT, 140.3 +/- 40.6 ms) were demonstrated in these patients. There was no statistically significant difference in the E/A ratio and DT between the 2 groups. Group I children were older (14.4 +/- 3.7 vs. 9.3 +/- 4.5 years; p = 0.015) and had lower MPI (0.20 +/- 0.02 vs. 0.28 +/- 0.07; p = 0.031) than Group II children. CONCLUSION: The children treated with chemotherapy using the TPOG protocol had a shorter IRT, higher E/A ratio and shorter DT. No significant evidence of anthracycline-related cardiotoxicity was found in any of the children in this study undergoing chemotherapy with the TPOG protocol.

Coexistence of peripheral primitive neuroectodermal tumor and tetralogy of Fallot.

We describe a little girl with tetralogy of Fallot (TOF) who was found to have a huge peripheral primitive neuroectodermal tumor (pPNET) when she developed progressive difficulty in standing and crawling at the age of 11 months. The tumor was located in the left paraspinal region (T4-T12), with intraspinal extension causing severe compression. Nine days after surgical decompression with laminectomy, chemotherapy was initiated with alternative courses of vincristine, doxorubicin, cyclophosphamide, etoposide, and ifosfamide every 3 weeks. The muscle power in her legs recovered substantially after 2 courses of chemotherapy. Although peripheral blood for cytogenetic study revealed no chromosome abnormality, recent cytogenetic analysis has revealed a high frequency of reciprocal translocation t(11;22)(q24;q12) detected in pPNET and a strong association between TOF and chromosome 22q11 microdeletion (del 22q11). Both genetic defects involve chromosome 22q in the close region. This case report illustrates the necessity of investigating for cytogenetic change in chromosome 22 and close follow-up due to the possibility of subsequent development of malignancies in patients with TOF.