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OBJECTIVES: Ultrasound (US) imaging has been observed to underestimate tumor size in clinical practice. This study aims to compare the size measurements of breast cancer and benign tumors using two-dimensional ultrasound (2DUS) and contrast-enhanced ultrasound (CEUS). METHODS: The study included 42 clinically confirmed breast cancer and 47 benign breast tumors. Two experienced physicians independently measured the maximal longitudinal and transverse diameters of the masses in 2DUS and CEUS. All analyses were performed in R (4.2.2) and GraphPad Prism 6. RESULTS: The maximal longitudinal and transverse diameters of breast cancer measured by CEUS were 26.61 ± 0.21% and 26.24 ± 0.19% larger compared with 2DUS, and benign breast tumors had an 11.74 ± 0.21% and 11.06 ± 0.14% increase in size compared with 2DUS. The area under the curve (AUC) of the receiver operating characteristic curve (ROC) for the difference between 2DUS and CEUS was 0.870 for longitudinal diameters (95% CI: 0.795-0.945, sensitivity 0.842, specificity 0.783, threshold value 0.215), and 0.863 for transverse diameters (95% CI: 0.785-0.942, sensitivity 0.667, specificity 0.936, threshold value 0.203). CONCLUSIONS: The size measurements of both breast cancer and benign tumors were larger in CEUS compared with 2DUS, with CEUS measurements of breast cancer being more pronounced than those of benign breast tumors. These findings suggest that CEUS may provide a more precise assessment of tumor size, which is crucial for determining optimal treatment strategies and improving patient outcomes in breast cancer management.
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Neoplasias de la Mama , Mama , Medios de Contraste , Aumento de la Imagen , Sensibilidad y Especificidad , Ultrasonografía Mamaria , Humanos , Femenino , Neoplasias de la Mama/diagnóstico por imagen , Neoplasias de la Mama/patología , Persona de Mediana Edad , Ultrasonografía Mamaria/métodos , Aumento de la Imagen/métodos , Adulto , Reproducibilidad de los Resultados , Mama/diagnóstico por imagen , Mama/patología , Anciano , Diagnóstico Diferencial , Carga TumoralRESUMEN
BACKGROUND: People living with a cancer diagnosis often experience cancer-related fatigue (CRF). Between 9% and 45% of people report CRF as moderate to severe, negatively impacting their quality-of-life (QOL). The evidence-base for managing CRF recommends exercise-related therapies over pharmaceutical interventions. One such exercise-like therapy is Baduanjin mind-body exercise (MBE), which has additional benefits. A remotely delivered program may further benefit people with CRF. The primary objective of this pilot will test study feasibility of a remotely delivered Baduanjin MBE exercise program for people living with CRF. METHODS: This is a randomized wait-list controlled pilot study and will take place in Sydney, Australia. Subject to informed consent, 40 adults with moderate CRF levels and receiving or previously received adjuvant chemotherapy, will undertake a home-based 8-week Baduanjin MBE program supported by online resources and instructors. The primary feasibility outcomes are recruitment, enrollment, retention, and adherence rates; and safety as measured by tolerance and adverse-event frequency. Clinical outcomes (eg, changes in CRF, QOL, and participant perceptions) are assessed at pre-intervention, week 1, week 4, week 8, and post-intervention. Analyses follows the Intent-to-Treat (all participants as per randomization) and per-protocol (participants adhering to the protocol). Missing data will be imputed from previous data entries and regression models may be tested to predict missing outcomes. DISCUSSION: To our knowledge, this is the first study evaluating the feasibility and effects of Baduanjin MBE on CRF using a remote delivery method. These feasibility data will inform a fully powered future trial investigating evidence of effect on CRF and QOL.Trial registration: Australian and New Zealand Clinical Trials Registry (ANZCTR 12623000177651).Ringgold ID: 651498 Chinese Medicine Centre.
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Neoplasias , Calidad de Vida , Adulto , Humanos , Estudios de Factibilidad , Australia , Terapia por Ejercicio/métodos , Neoplasias/complicaciones , Fatiga/etiología , Fatiga/terapia , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
INTRODUCTION: Frailty is one of the most common comorbidities in kidney transplant recipients (KTRs). Physical, psychological and social frailty could be improved by exercise intervention. Baduanjin, also known as Eight-section Brocades, is a type of traditional Chinese medicine exercise characterised by the interplay between physical postures and movements, breathing and mind. It can help frail patients strengthen their upper and lower body muscles, improve their mood, quality of life and frailty. However, the effectiveness of Baduanjin on frail KTRs remains unknown. Therefore, we will conduct a randomised controlled trial (RCT) to evaluate the effectiveness of Baduanjin on frail KTRs. METHODS AND ANALYSIS: This protocol describes an assessor and analyst blinded, parallel RCT for frail KTRs comparing Baduanjin group (n=72) with care-as-usual group (n=72). The primary outcomes are frailty assessed by Frailty Phenotype scale and Tilburg Frailty Indicator scale, and muscle strength assessed by a grip strength metre. The secondary outcomes are quality of life assessed by Medical Outcomes Study 36-Item Short-Form Health Survey (MOS SF-36) and depression assessed by the Hospital Anxiety and Depression Scale. All these data will be collected at the baseline, after 3, 6, 9 and 12 months, respectively. Two-way mixed analysis of variance (ANOVA) will be used to test the effectiveness of Baduanjin exercise. Qualitative interviews with participants in the intervention group will also be performed after 6 months. Themes will be extracted from interview transcripts using NVivo software. ETHICS AND DISSEMINATION: The Ethics Committees of Beijing University of Chinese Medicine (2022BZYLL1018) and China-Japan Friendship Hospital (2022-KY-250) had approved the study. The organ donors were all from China-Japan Friendship Hospital. They provided informed consent and they were not executed prisoners. We have provided BMJ Open with documentation from the hospital that indicates that the organs will be harvested ethically. The findings of this study will be disseminated through peer-reviewed journals, international conferences, media reports and briefings. TRIAL REGISTRATION NUMBER: ChiCTR2100041730.
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Fragilidad , Trasplante de Riñón , Humanos , Anciano , Anciano Frágil , Receptores de Trasplantes , Terapia por Ejercicio , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
Chronic hepatitis B (CHB) remains a significant health challenge worldwide. The current treatments for CHB achieve less than 10% cure rates, majority of the patients are on therapy for life. Therefore, cure of CHB is a high unmet medical need. HBV surface antigen (HBsAg) loss and seroconversion are considered as the key for the cure. RG7834 is a novel, orally bioavailable small molecule reported to reduce HBV antigens. Based on RG7834 chemistry, we designed and discovered a series of dihydrobenzopyridooxazepine (DBP) series of HBV antigen inhibitors. Extensive SAR studies led us to GST-HG131 with excellent reduction of HBV antigens (both HBsAg and HBeAg) in vitro and in vivo. GST-HG131 improved safety in rat toxicology studies over RG7834. The promising inhibitory activity, together with animal safety enhancement, merited GST-HG131 progressed into clinical development in 2020 (NCT04499443).
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Hepatitis B Crónica , Hepatitis B , Animales , Ratas , Antígenos de Superficie , Antivirales/farmacología , Antivirales/uso terapéutico , ADN Viral , Hepatitis B/tratamiento farmacológico , Antígenos e de la Hepatitis B/uso terapéutico , Antígenos de Superficie de la Hepatitis B , Virus de la Hepatitis B , Hepatitis B Crónica/tratamiento farmacológicoRESUMEN
Background: The capacity to distinguish hypertrophic cardiomyopathy (HCM) from hypertensive left ventricular hypertrophy (H-LVH) based on morphological features obtained by conventional echocardiography is limited. We investigated the global myocardial work of the left ventricle in two types of hypertrophies using the non-invasive myocardial work index (NMWI). Methods: Conventional echocardiography was performed on 107 subjects with preserved left ventricular ejection fraction (LVEF ≥ 50%), who comprised patients with HCM (n = 40), H-LVH (n = 35), and healthy people with normal blood pressure and left ventricular structure (n = 32). Except for the conventional echocardiographic parameters, the left ventricular myocardial work parameters based on pressure-strain loops, including global myocardial work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE), were evaluated in three groups. Multivariate discriminant analysis and receiver operating characteristic (ROC) curve were used to evaluate the incremental value of NMWI for distinguishing HCM from H-LVH. Results: Compared to the control group, GWI and GCW were significantly lower in HCM patients (P < 0.05), whereas GWI was significantly higher in H-LVH patients. GWW was higher and GWE was significantly decreased in both HCM and H-LVH patients than in the control group (P < 0.05). Multivariate discriminant analysis and ROC curve revealed that the inter-ventricular septum thickness (IVST)/left ventricular posterior wall thickness (LVPWT) and GCW were each able to distinguish HCM from H-LVH. The combination of IVST/LVPWT and GCW discriminated HCM and H-LVH with a higher predictive accuracy of 94.7%. Conclusion: NMWI may provide additional information in evaluating the myocardial function in patients with HCM and H-LVH. Myocardial work combined with conventional echocardiography could improve the clinical diagnostic accuracy of distinguishing HCM and H-LVH.
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Background: Coronary artery disease (CAD) can lead to left ventricular (LV) remodeling, which, in adverse cases, has been associated with heart failure and increased mortality. Here, we aimed to evaluate the predictive value of the noninvasive myocardial work index (NIMWI) for LV reverse remodeling in patients with multivessel CAD after percutaneous coronary intervention (PCI). Methods: A total of 88 consecutive patients with multivessel CAD treated with PCI were identified and categorized according to the presence of LV reverse remodeling 3 months after PCI [≥15% decrease in the LV end diastolic volume (LVEDV)]. With the LV pressure-strain loop (PSL) technique, NIMWIs, including the global work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE), were statistically compared between the reverse LV remodeling group and nonreverse LV remodeling group 1 week before PCI. Results: Significantly lower GWI, GCW, and GWE, and significantly higher GWW were observed in the reverse LV remodeling group compared with the nonreverse LV remodeling group (P<0.05). Left ventricular mass index (LVMI), GCW, and GWE were independently associated with early LV reverse remodeling. Receiver operating characteristic (ROC) curve analysis demonstrated that GCW was the most powerful predictor of early LV reverse remodeling in patients with CAD [area under the curve (AUC) =0.867]. The optimal cutoff GCW value predictive of early LV reverse remodeling was 1,438.5 mmHg% (sensitivity, 85%; specificity, 70%). Conclusions: GCW, among the NIMWIs, may be the major predictor of LV reverse remodeling in patients with multivessel CAD after PCI. NIMWI could potentially provide a new reference index for the quantitative evaluation of LV myocardial work.
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GST-HG131, a novel dihydroquinolizinone (DHQ) compound, has been shown to reduce circulating levels of HBsAg in animals. This first-in-human trial evaluated the safety, tolerability, and pharmacokinetic profile of GST-HG131 in healthy Chinese subjects. This was a double-blind, randomized, placebo-controlled phase Ia clinical trial that was conducted in two parts. Part A was a single-ascending-dose (SAD; GST-HG131 10 30, 60, 100, 150, 200, 250 or 300 mg or placebo) study, which also assessed the food effect of GST-HG131 100 mg. Part B was a multiple-ascending-dose (MAD; GST-HG131 30, 60 or 100 mg or placebo BID) study. Tolerability assessments included adverse events, vital signs, 12-lead electrocardiogram, physical examination, and clinical laboratory tests. PK analyses were conducted in blood, urine, and fecal samples. Single doses of GST-HG131 ≤ 300 mg and multiple doses of GST-HG131 ≤ 60 mg were generally safe and well tolerated; however, multiple dosing was stopped at GST-HG131 100 mg, as pre-defined stopping rules specified in the protocol were met (Grade II drug related AEs of nausea and dizziness in >50% of subjects). In the SAD study, median tmax of GST-HG131 was 1-6 h, and t1/2 ranged from 3.88 h to 14.3 h. PK parameters were proportional to dose. Exposure was reduced after food intake. In the MAD study, steady-state was attained on day 4, and there was no apparent plasma accumulation of GST-HG131 on day 7 (Racc < 1.5). In conclusion, GST-HG131 exhibited an acceptable safety profile in healthy subjects at single doses ranging from 10-300 mg and multiple doses (BID) ranging from 30-60 mg, and the MAD doses (30 mg and 60 mg BID) that potentially meet the therapeutic AUC requirements. These findings imply GST-HG131 has potential as a therapeutic option for CHB infection. (This study has been registered at ClinicalTrials.gov under identifier NCT04499443.).
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Virus de la Hepatitis B , Área Bajo la Curva , China , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Voluntarios Sanos , HumanosRESUMEN
BACKGROUND: Accurate evaluation of left ventricular (LV) systolic function is the premise for diagnosing and treating chronic heart failure. This study aimed to explore the incremental value of echocardiographic myocardial work in evaluating the LV systolic dysfunction in patients with chronic heart failure. METHODS: A total of 206 participants were enrolled, including 155 patients with chronic heart failure and 51 healthy controls (HC). The chronic heart failure patients were divided into three groups according to LV ejection fraction (LVEF): Heart failure with preserved ejection fraction (HFpEF group, 54 cases, LVEF ≥50%), heart failure with mid-range ejection fraction (HFmrEF group, 50 cases, 40%≤ LVEF <50%), and heart failure with reduced ejection fraction (HFrEF group, 51 cases, LVEF <40%). Except for the conventional echocardiographic parameters, the left ventricular myocardial work parameters, including the global myocardial work index (GWI), global constructive work (GCW), global wasted work (GWW), and global work efficiency (GWE), were calculated in the study participants. One-way analysis of variance test followed by Fisher's least significant difference (LSD) t-test were used to obtain parameters with significant differences, which were then fed into a machine learning model established for subsequent multi-classification of the four groups. The selected myocardial work parameters with high importance rankings resulting from the machine learning model were further compared with the traditional LVEF in the multi-classification of the four groups. RESULTS: All conventional echocardiographic parameters were significantly different between the HFmrEF and HFrEF groups, but only E/e', left atrium showed notable differences between the HFpEF and HC groups (P<0.05). All myocardial work parameters were markedly different between the four groups (P<0.05). LVEF and GWI were more important than the other parameters according to the multi-classification machine learning model. The multi-classification diagnostic performances of LVEF, GWI, and LVEF + GWI were 82%, 88%, and 98%, respectively, which confirmed that GWI + LVEF could complementarily improve the diagnosis accuracy in classifying the four groups, with a performance increase of approximately 10% than each individually. CONCLUSIONS: GWI can play a complementary role to LVEF in the early diagnosis of HFpEF patients from the HC group and improve the clinical evaluation accuracy in chronic heart failure patients. Echocardiographic myocardial work should be utilized along with conventional LVEF to evaluate the systolic function of chronic heart failure patients in clinical practice.
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Background: Mitral valve (MV) morphology after MV repair affects postoperative left ventricular (LV) blood flow pattern and long-term cardiac function. Pilot data suggest that LV diastolic vortex flow pattern changes after operation, but specific quantifiers remain unknown. We aimed to explore the role of vector flow mapping (VFM) in LV diastolic vortex flow pattern in patients who underwent MV repair. Methods: A total of 70 patients with degenerative mitral regurgitation were consecutively enrolled and 30 age- and gender-matched controls were recruited. 50 Patients who underwent MV repair were eventually included in our study. LV average energy loss (EL-AVE) during diastole was measured in the MV repair group by VFM one week before and one month after the operation, and compared with that of controls using one-way analysis of variance. The effect of surgical techniques and the extension of leaflet degeneration on postoperative EL-AVE were analyzed using muti-way analysis of variance, and patients were categorized into a resection subgroup (n = 29) and a non-resection subgroup (n = 21). Results: The EL-AVE one month after operation in the MV repair group was decreased (p < 0.001) compared to that one week before the operation, and was increased (p < 0.001) compared to that in controls. Mitral leaflet resection had a statistically significant effect on postoperative EL-AVE. The EL-AVE of the resection subgroup was higher than that of non-resection subgroup (p < 0.001). Conclusions: VFM can be used to evaluate the diastolic blood flow pattern of LV after MV repair, and to observe the changes of LV blood flow pattern caused by different surgical techniques. VFM may be a potential new hemodynamic evaluation method after MV repair.
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Background: Type 2 diabetes mellitus (T2DM) is a common risk factor for cardiovascular diseases. The aims of this study were to evaluate the changes in the left ventricular myocardial work in T2DM patients using the left ventricular pressure-strain loop (PSL) technique, and to explore the risk factors for the left ventricular myocardial work impairment. Methods: Fifty patients with T2DM and 50 normal controls (NCs) were included in the study. In addition to conventional echocardiography and two-dimensional speckle tracking echocardiography, the left ventricular myocardial work parameters were measured using PSL technology. Results: The absolute value for global longitudinal strain (GLS), global work index (GWI) and, global constructive work (GCW) were significantly decreased in the T2DM group (P < 0.05), while the left ventricular ejection fraction (LVEF) was not significantly different between the T2DM and NC groups. Multivariable linear regression analysis showed that hemoglobin A1c (HbA1c) was independently related to GWI (ß = -0.452, P < 0.05), while HbA1c and the diabetes duration were independently related to GCW (ß = -0.393, P < 0.05 and ß = -0.298, P < 0.05, respectively). Conclusions: Changes in the left ventricular myocardial systolic function in T2DM patients were identified using PSL technology. HbA1c was shown to be an independent risk factor affecting GWI, while HbA1c and diabetes duration were demonstrated to be independent risk factors affecting GCW.
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Objectives: To analyze the association between global myocardial work indices evaluated by non-invasive left ventricular (LV) pressure-strain loop (PSL) and LV myocardial fibrosis in patients with dilated cardiomyopathy (DCM). Methods: A total of 57 patients with DCM were included in this prospective study. Global work index (GWI), global constructive work (GCW), global wasted work (GWW), global work efficiency (GWE) and global longitudinal strain (GLS) were measured using LVPSL. LV volumes and LV ejection fraction (LVEF) were evaluated using cardiac magnetic resonance imaging (CMRI), LV myocardial fibrosis was estimated at CMRI by qualitative assessment of late gadolinium enhancement (LGE). According to the CMRI, the studied population was divided into two groups, namely: patients without LGE (LGE-) and patients with LGE (LGE+). Results: The LGE+ group presented with increased age, LV end systolic volume (LVESV) index and reduced GWI, GCW, GWE, GLS, CMRI-derived LVEF (LVEFCMRI), the differences between the two groups were statistically significant (P < 0.05). After correcting for age and LVESV index, LVEFCMRI, GLS, GWI, GCW, and GWE retained independent associations with LV myocardial fibrosis. According to receiver operating characteristics (ROC) analysis, LVEFCMRI, and GCW showed larger AUC and higher accuracy, sensitivity, and specificity than GLS, the accuracy of predicting LV myocardial fibrosis ranged from high to low as: LVEFCMRI, GCW, GWE, GWI, and GLS. Conclusions: LVEFCMRI, GWI, GCW, GWE, and GLS remained significant predictors of LV myocardial fibrosis. LVEFCMRI, and GCW appeared to better predict LV myocardial fibrosis compared with GLS.
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The aim of our prospective pilot study was to explore the distribution characteristics of myocardial work (MW) of patients with dilated cardiomyopathy (DCM) and their clinical value in evaluation of therapeutic effects. Thirty patients with DCM were enrolled in the case group, and 30 healthy patients were randomly allocated to the control group. Global myocardial work (GMW) and regional myocardial work (RMW) of the control and case groups before and after therapy were evaluated by using left ventricular pressure-strain loops and then compared. We found significant differences in GMW and RMW between the control and case groups (p < 0.05). Compared with before therapy, the global work index and 6-min walking distance increased, but LV ejection fraction and global longitudinal strain did not significantly change after therapy. GMW was significantly correlated with LV ejection fraction and global longitudinal strain (p < 0.01). Bland-Altman plot analysis revealed that GMW values were consistent between and within the groups. The results suggest that LV MW values were diffusely impaired in patients with DCM and that the global work index may be used as an indicator in evaluation of therapeutic effects.
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Cardiomiopatía Dilatada/fisiopatología , Ventrículos Cardíacos/fisiopatología , Presión Ventricular , Adulto , Cardiomiopatía Dilatada/tratamiento farmacológico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Estudios Prospectivos , Adulto JovenAsunto(s)
Estenosis de la Válvula Aórtica/fisiopatología , Velocidad del Flujo Sanguíneo/fisiología , Ecocardiografía Doppler en Color/métodos , Ventrículos Cardíacos/fisiopatología , Contracción Miocárdica/fisiología , Volumen Sistólico/fisiología , Función Ventricular Izquierda/fisiología , Anciano , Estenosis de la Válvula Aórtica/diagnóstico , Diástole , Progresión de la Enfermedad , Femenino , Estudios de Seguimiento , Ventrículos Cardíacos/diagnóstico por imagen , Humanos , Masculino , Persona de Mediana Edad , Estudios RetrospectivosRESUMEN
The first national-scale assessment of lead (Pb) contamination in agricultural soils across China was conducted based on >1900 articles published between 1979 and 2016. Pb concentrations, temporal and spatial variations, and influencing factors were analyzed. Children's blood lead levels (BLLs) were also estimated using the integrated exposure uptake biokinetic (IEUBK) model. Pb concentrations in different areas of China varied greatly, which was closely associated with the distribution of Pb-related industries, especially Pb-zinc mine smelting, non-ferrous polymetallic mine smelting, e-waste recycling, and leaded gasoline consumption. The year 2000 was a significant transition year for Pb concentrations, with a rapid increase pre-2000 and a subsequent slow upward trend. Pb concentrations were found to be strongly associated with indicators of economic and social development including gross domestic product (GDP), population size, and vehicle ownership. Leaded gasoline, coal combustion, and non-ferrous smelting were the main sources of atmospheric Pb during the different periods. Predicted BLLs were higher in South China than those in the north. This study details the overall Pb contamination status of agricultural soils in China, and thus provides insights for policymakers with respect to pollution prevention measures.
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Desarrollo Económico , Monitoreo del Ambiente , Plomo/análisis , Cambio Social , Contaminantes del Suelo/análisis , China , Producto Interno Bruto/estadística & datos numéricos , Vehículos a Motor/estadística & datos numéricos , Propiedad/estadística & datos numéricos , Densidad de PoblaciónRESUMEN
BACKGROUND: Accessory mitral valve tissue rarely causes left ventricular outflow tract obstruction in adults. It is often associated with other cardiac and vascular congenital malformations. Here, we report the rarest presentation of accessory mitral valve tissue (AMVT) causing left ventricular outflow tract obstruction. CASE SUMMARY: A 22-year-old female patient presented with a history of shortness of breath and chest pain for more than 5 years. A diagnosis of AMVT with parachute mitral valve, ventricular septal defect (VSD), bicuspid aortic valve, unruptured aneurysm of aortic sinus, and left ventricular outflow tract obstruction was made. Successful closure of VSD with mitral valve replacement, excision of AMVT, and repair of the aortic sinus were performed. The post-operative course was uneventful, and an echocardiogram showed complete resection of the accessory mitral valve, no residual shunt and no left ventricular outflow gradient. Additionally, the peak gradient of rapid filling phase and atrial systolic phase across the prosthetic mitral valve were 16 mmHg and 4 mmHg, respectively. The peak velocity across left ventricular outflow tract was 1.4 m/s. DISCUSSION: Accessory mitral valve tissue is associated with other cardiac abnormalities and is usually diagnosed in the first or second decade of life. It is responsible for left ventricular outflow tract obstruction. The obstruction can occur in the early period of life due to continued deposition of fibrous tissues within left ventricular outflow tract. Accessory mitral valve tissue should be considered a rare but important cause of left ventricular outflow tract obstruction.
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A Friedel-Crafts alkylation of pyrrole was developed to afford the ß,γ-unsaturated α-hydroxy esters bearing a quaternary stereogenic center with good enantioselectivities and yields. This protocol represents the first report of 1,2-addition of Friedel-Crafts alkylation of pyrrole to ß,γ-unsaturated α-ketoesters.
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A primary amine-catalyzed asymmetric formal aza-Diels-Alder reaction of trifluoromethyl hemiaminals with enones was developed via a chiral gem-diamine intermediate. This novel protocol allowed facile access to structurally diverse trifluoromethyl-substituted piperidine scaffolds with high stereoselectivity. The utility of this method was further demonstrated through a concise approach to biologically active 4-hydroxypiperidine. More importantly, a stepwise mechanism involving an asymmetric induction process was proposed to rationalize the positive correlation between the chirality of the gem-diamine intermediate and the formal aza-Diels-Alder product.
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The highly enantioselective hetero-Diels-Alder reaction of Danishefsky's diene with glyoxals was developed by virtue of a readily accessible chiral copper catalyst. This efficient transformation provided a facile and scalable access to a wide range of biologically active dihydropyrones with a high level of enantioselectivities. Moreover, the substrate scope of this reaction could be extended to isatins with this catalytic system. More importantly, the mechanism involved in this reaction was proposed on the basis of the unambiguous structures of intermediates.
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A general organocatalytic asymmetric dehydrated Mannich reaction of fluoroalkyl hemiaminals with ketones is reported. In this Mannich reaction, previously less explored aryl ketones showed great reactivity. By virtue of this efficient method, a wide range of biologically active ß-amino ketones were directly obtained. More importantly, two different intermediates involved in the reaction were detected and identified by (19)F NMR and HRMS analysis. Furthermore, the synthetic utility of the products was demonstrated by the synthesis of the biologically active fluoroalkyl ß-amino alcohols.
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A highly enantioselective Friedel-Crafts alkylation of pyrrole to ß,γ-unsaturated α-ketoesters was developed by virtue of a chiral copper complex, affording the alkylated derivatives of pyrrole with good yields and excellent enantioselectivities. Moreover, merging copper catalysis with gold catalysis realized a one-pot construction of the seven-membered ring to give annulated pyrroles with moderate to good yields and high enantiomeric excesses.