ABSTRACT
The maintenance of genome integrity in the germline is crucial for mammalian development. Long interspersed element type 1 (LINE-1, L1) is a mobile genetic element that makes up about 17% of the human genome and poses a threat to genome integrity. N6-methyl-adenosine (m6A) plays an essential role in regulating various biological processes. However, the function of m6A modification in L1 retrotransposons and human germline development remains largely unknown. Here we knocked out the m6A methyltransferase METTL3 or the m6A reader YTHDF2 in human embryonic stem cells (hESCs) and discovered that METTL3 and YTHDF2 are crucial for inducing human spermatogonial stem cells (hSSCs) from hESCs in vitro. The removal of METTL3 or YTHDF2 resulted in increased L1 retrotransposition and reduced the efficiency of SSC differentiation in vitro. Further analysis showed that YTHDF2 recognizes the METTL3-catalyzed m6A modification of L1 retrotransposons and degrades L1 mRNA through autophagy, thereby blocking L1 retrotransposition. Moreover, the study confirmed that m6A modification in human fetal germ cells promotes the degradation of L1 retrotransposon RNA, preventing the insertion of new L1 retrotransposons into the genome. Interestingly, L1 retrotransposon RNA was highly expressed while METTL3 was significantly downregulated in the seminal plasma of azoospermic patients with meiotic arrest compared to males with normal fertility. Additionally, we identified some potentially pathogenic variants in m6A-related genes in azoospermic men with meiotic arrest. In summary, our study suggests that m6A modification serves as a guardian of genome stability during human germline development and provides novel insights into the function and regulatory mechanisms of m6A modification in restricting L1 retrotransposition.
Subject(s)
Azoospermia , Retroelements , Male , Animals , Humans , Retroelements/genetics , RNA , Azoospermia/genetics , Cell Differentiation/genetics , Methyltransferases/genetics , Methyltransferases/metabolism , RNA, Messenger/genetics , Mammals/metabolismABSTRACT
AIMS: This study aims to outline the 'true' natural history of ascending thoracic aortic aneurysm (ATAA) based on a cohort of patients not undergoing surgical intervention. METHODS AND RESULTS: The outcomes, risk factors, and growth rates of 964 unoperated ATAA patients were investigated, over a median follow-up of 7.9 (maximum of 34) years. The primary endpoint was adverse aortic events (AAE), including dissection, rupture, and aortic death. At aortic sizes of 3.5-3.9, 4.0-4.4, 4.5-4.9, 5.0-5.4, 5.5-5.9, and ≥6.0 cm, the average yearly risk of AAE was 0.2%, 0.2%, 0.3%, 1.4%, 2.0%, and 3.5%, respectively (P < 0.001), and the 10-year survival free from AAE was 97.8%, 98.2%, 97.3%, 84.6%, 80.4%, and 70.9%, respectively (P < 0.001). The risk of AAE was relatively flat until 5 cm of aortic size, at which it began to increase rapidly (P for non-linearity <0.001). The mean annual growth rate was estimated to be 0.10 ± 0.01 cm/year. Ascending thoracic aortic aneurysms grew in a very slow manner, and aortic growth over 0.2 cm/year was rarely seen. Multivariable Cox regression identified aortic size [hazard ratio (HR): 1.78, 95% confidence interval (CI): 1.50-2.11, P < 0.001] and age (HR: 1.02, 95% CI: 1.00-1.05, P = 0.015) as significant independent risk factors for AAE. Interestingly, hyperlipidemia (HR: 0.46, 95% CI: 0.23-0.91, P = 0.025) was found to be a significant protective factor for AAE in univariable Cox regression. CONCLUSION: An aortic size of 5 cm, rather than 5.5 cm, may be a more appropriate intervention criterion for prophylactic ATAA repair. Aortic growth may not be an applicable indicator for intervention.
Subject(s)
Aortic Aneurysm, Thoracic , Aortic Aneurysm , Aortic Dissection , Aortic Rupture , Humans , Aortic Dissection/epidemiology , Aortic Dissection/surgery , Universities , Aortic Aneurysm/surgery , Aorta , Aortic Aneurysm, Thoracic/epidemiology , Aortic Aneurysm, Thoracic/surgery , Risk Factors , Retrospective Studies , Aortic Rupture/surgeryABSTRACT
In this paper, a novel Multi-Objective Hypergraph Particle Swarm Optimization (MOHGPSO) algorithm for structural health monitoring (SHM) systems is considered. This algorithm autonomously identifies the most relevant sensor placements in a combined fitness function without artificial intervention. The approach utilizes six established Optimal Sensor Placement (OSP) methods to generate a Pareto front, which is systematically analyzed and archived through Grey Relational Analysis (GRA) and Fuzzy Decision Making (FDM). This comprehensive analysis demonstrates the proposed approach's superior performance in determining sensor placements, showcasing its adaptability to structural changes, enhancement of durability, and effective management of the life cycle of structures. Overall, this paper makes a significant contribution to engineering by leveraging advancements in sensor and information technologies to ensure essential infrastructure safety through SHM systems.
ABSTRACT
The present study aimed to assess the impact of anthropogenic stressors on the physico-chemical characteristics and water quality of the River Ganga employing a GIS-based approach in the middle Gangetic Plain at Patna, India. After the survey, sand mining, bridge construction, and disposal of untreated domestic and sewage wastes were selected as major anthropogenic stressors. A total of 48 samples were collected in pre-monsoon and post-monsoon seasons of 2022 and were analyzed for 16 physico-chemical parameters, namely water temperature (WT), pH, electrical conductivity (EC), total dissolved solids (TDS), turbidity, dissolved oxygen (DO), biological oxygen demand (BOD), total hardness (TH), Ca2+, Mg2+, Na+, K+, Cl- and SO42- ions, following standard protocols. The WQI was calculated using the Weighted Arithmetic Water Quality Index (WAQWI) method and spatial maps were created using ArcGIS software. The result revealed significant seasonal variation in several physico- chemical parameters except for Ca2+, K+ and TA (p > 0.05). ANOVA revealed significant variation for BOD and COD at Ghagha and Triveni, whereas for nitrate at Gai Ghat reference and impact sites, respectively. The Water Quality Index (WQI) revealed a deterioration in water quality by 60% in post-monsoon season. HCA revealed that the WQI was mostly governed by TDS, TH, TA, and EC.
Subject(s)
Anthropogenic Effects , Geographic Information Systems , Rivers , Water Quality , IndiaABSTRACT
While still rare, cationic ligands offer much promise as tunable electron-withdrawing ligands for π-acid catalysis. Recently, we introduced pincer-type sulfonium cations into the list of available strongly π-acidic ancillary ligands. However, the M-S bond in sulfonium complexes of these ligands was found highly labile, precluding their catalytic applications. Herein we demonstrate that this obstacle can be overcome by increasing the rigidity of the sulfonium pincer scaffold. X-ray analyses confirm that despite bearing a formal positive charge, the sulfur atom of this newly designed sulfonium ligand maintains its coordination to the Pt(II)-center, while DFT calculations indicate that by doing so it strongly enhances the electrophilic character of the metal. Kinetic studies carried out on three model cycloisomerization reactions prove that such a tris-cationic sulfonium-Pt(II) complex is highly reactive, compared to its thioether-based analogue. This proof-of-concept study presents the first example of employing sulfonium-based ligands in homogeneous catalysis.
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Novel vaccination strategies are crucial to efficiently control tuberculosis, as proposed by the World Health Organization under its flagship program "End TB Strategy." However, the emergence of drug-resistant strains of Mycobacterium tuberculosis (Mtb), particularly in those coinfected with HIV-AIDS, constitutes a major impediment to achieving this goal. We report here a novel vaccination strategy that involves synthesizing a formulation of an immunodominant peptide derived from the Acr1 protein of Mtb. This nanoformulation in addition displayed on the surface a toll-like receptor-2 ligand to offer to target dendritic cells (DCs). Our results showed an efficient uptake of such a concoction by DCs in a predominantly toll-like receptor-2-dependent pathway. These DCs produced elevated levels of nitric oxide, proinflammatory cytokines interleukin-6, interleukin-12, and tumor necrosis factor-α, and upregulated the surface expression of major histocompatibility complex class II molecules as well as costimulatory molecules such as CD80 and CD86. Animals injected with such a vaccine mounted a significantly higher response of effector and memory Th1 cells and Th17 cells. Furthermore, we noticed a reduction in the bacterial load in the lungs of animals challenged with aerosolized live Mtb. Therefore, our findings indicated that the described vaccine triggered protective anti-Mtb immunity to control the tuberculosis infection.
Subject(s)
Mycobacterium tuberculosis , Tuberculosis , Animals , Dendritic Cells , Epitopes , Ligands , Mycobacterium tuberculosis/metabolism , Toll-Like Receptor 2/metabolism , Tuberculosis/prevention & control , Tuberculosis/microbiology , MiceABSTRACT
Ascending thoracic aortic aneurysms may be fatal upon rupture or dissection and remain a leading cause of death in the developed world. Understanding the pathophysiology of the development of ascending thoracic aortic aneurysms may help reduce the morbidity and mortality of this disease. In this review, we will discuss our current understanding of the protective relationship between ascending thoracic aortic aneurysms and the development of atherosclerosis, including decreased carotid intima-media thickness, low-density lipoprotein levels, coronary and aortic calcification, and incidence of myocardial infarction. We also propose several possible mechanisms driving this relationship, including matrix metalloproteinase proteins and transforming growth factor-ß.
Subject(s)
Aneurysm , Aortic Aneurysm, Thoracic , Atherosclerosis , Humans , Carotid Intima-Media Thickness , Atherosclerosis/metabolismABSTRACT
This issue of the Yale Journal of Biology and Medicine (YJBM) focuses on Big Data and precision analytics in medical research. At the Aortic Institute at Yale New Haven Hospital, the vast majority of our investigations have emanated from our large, prospective clinical database of patients with thoracic aortic aneurysm (TAA), supplemented by ultra-large genetic sequencing files. Among the fundamental clinical and scientific discoveries enabled by application of advanced statistical and artificial intelligence techniques on these clinical and genetic databases are the following: From analysis of Traditional "Big Data" (Large data sets). 1. Ascending aortic aneurysms should be resected at 5 cm to prevent dissection and rupture. 2. Indexing aortic size to height improves aortic risk prognostication. 3. Aortic root dilatation is more malignant than mid-ascending aortic dilatation. 4. Ascending aortic aneurysm patients with bicuspid aortic valves do not carry the poorer prognosis previously postulated. 5. The descending and thoracoabdominal aorta are capable of rupture without dissection. 6. Female patients with TAA do more poorly than male patients. 7. Ascending aortic length is even better than aortic diameter at predicting dissection. 8. A "silver lining" of TAA disease is the profound, lifelong protection from atherosclerosis. From Modern "Big Data" Machine Learning/Artificial Intelligence analysis: 1. Machine learning models for TAA: outperforming traditional anatomic criteria. 2. Genetic testing for TAA and dissection and discovery of novel causative genes. 3. Phenotypic genetic characterization by Artificial Intelligence. 4. Panel of RNAs "detects" TAA. Such findings, based on (a) long-standing application of advanced conventional statistical analysis to large clinical data sets, and (b) recent application of advanced machine learning/artificial intelligence to large genetic data sets at the Yale Aortic Institute have advanced the diagnosis and medical and surgical treatment of TAA.
Subject(s)
Aortic Aneurysm, Thoracic , Aortic Dissection , Humans , Male , Female , Aortic Dissection/genetics , Artificial Intelligence , Prospective Studies , Aorta/pathology , Aortic Aneurysm, Thoracic/genetics , Aortic Aneurysm, Thoracic/diagnosisABSTRACT
Purpose: According to the 2020 American College of Cardiology/American Heart Association guidelines, the aortic valve should be replaced in the setting of severe aortic stenosis or regurgitation, independent of left ventricular function (even for EF < 55%). However, in clinical practice, especially in a very low EF range, surgeons may avoid surgical aortic valve replacement (SAVR) because of concern over operative risk. This study examines outcomes of patients with EF ≤ 35% undergoing SAVR. Methods: From 2004 to 2019, 895 patients underwent SAVR for aortic stenosis (AS) and/or regurgitation (AR) by a single surgeon at our institution. From among these, 40 patients (4.47%) had an ejection fraction (EF) of 35% or less, forming the study group. Intra-aortic balloon pump was placed intraoperatively prophylactically pre-bypass in 18 out of the 40. Preoperative and post-operative echocardiograms were compared to determine changes in ejection fraction. Mid-term survival was assessed. Results: 16 patients presented with AS, 20 with AR, and 4 with a combination of AS and AR. Hospital survival was 97.5% (one patient death). The average ejection fraction progressively improved over time from 26% initially to 46% mid-term with mean follow-up of 43 months (0.1-140.7). Remarkably, five-year survival was comparable between the study group and an age- and gender-matched general population (p = 0.834). Downward trends in LV end-diastolic diameter and end-systolic diameter were seen. The former achieved statistical significance (6.0 cm to 5.3 cm; p = 0.0046), while the latter fell slightly short (4.8 cm to 4.1 cm; p = 0.056). Patients in whom an IABP was used had lower EFs than those without IABP (range 10-35, mean 23% vs. 15-35%, mean 27.6%). The EFs of the three subgroups improved significantly postoperatively (p < 0.001 for AS, p = 0.002 for AR, and p = 0.046 for AS and AR). Conclusions: Surgical AVR can be done safely in patients with a failing LV with EF ≤ 35%. Significant improvements in the ejection fraction are seen over time. We believe there is a role for prophylactic pre-bypass IABP. Five-year survival is normalized. Surgeons should not hesitate to perform AVR in these highly jeopardized patients.
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PURPOSE: Loeys-Dietz syndrome (LDS) is a rare connective tissue disorder. In LDS patients with normal arch morphology, whether the arch should be prophylactically replaced at the time of proximal aortic replacement remains unknown. We evaluated the risk of long-term arch complications in genetically confirmed LDS patients who underwent proximal ascending aortic replacement. METHODS: We retrospectively reviewed the records of patients with LDS who have been followed at our institution between 1994 and 2020. Patients were only included if whole exome genetic testing confirmed a mutation in an LDS-causing gene (TGFBR1, TGFBR2, SMAD3, TGFB2, or TGFB3). Mutations were categorized as pathogenic, benign, or of unknown significance. We collected demographic information, aortic dimensions, comorbidities, mortality, and operative course from patients' charts. Descriptive statistics and freedom from reoperation plots were generated. RESULTS: Of the 18 patients with a mutation in an LDS-causing gene, 15 had known pathogenic variants, two had mutations of unknown significance, and one had a benign genetic variant. For the 15 patients with confirmed pathogenic variants of LDS the median follow-up duration was 5 years (interquartile range [IQR]: 4-8). Eleven patients underwent ascending aortic replacements (AAR) ± aortic valve replacement. Two patients required an additional operation; one required arch and staged elephant trunk for a dissection 18 years post-AAR and the other patient required an isolated descending aortic replacement for dissection 5 years post-AAR. Among patients who underwent surgery, the median ascending aortic diameter at intervention was 5.0 cm (IQR: 4.3-5.3). There was no surgical or late follow-up mortality observed for any of the 18 patients in the study. CONCLUSION: LDS patients who underwent proximal aortic replacement appeared to have low long-term risk of arch complications. While our study is somewhat limited by its sample size and follow-up duration, it suggests that routine prophylactic total arch replacement may not be warranted in LDS patients with nonaneurysmal aortic arches.
Subject(s)
Loeys-Dietz Syndrome , Humans , Loeys-Dietz Syndrome/complications , Loeys-Dietz Syndrome/genetics , Loeys-Dietz Syndrome/surgery , Receptor, Transforming Growth Factor-beta Type I , Receptor, Transforming Growth Factor-beta Type II/genetics , Retrospective Studies , Transforming Growth Factor beta3ABSTRACT
Unreliable networks often use excess bandwidth for data integration in smart cities. For this purpose, Messaging Queuing Telemetry Transport (MQTT) with a certain quality of service (QoS) is employed. Data integrity and data security are frequently compromised for reducing bandwidth usage while designing integrated applications. Thus, for a reliable and secure integrated Internet of Everything (IoE) service, a range of network parameters are conditioned to achieve the required quality of a deliverable service. In this work, a QoS-0-based MQTT is developed in such a manner that the transparent MQTT protocol uses Transmission Control Protocol (TCP)-based connectivity with various rules for the retransmission of contents if the requests are not entertained for a fixed duration. The work explores the ways to improve the overall content delivery probability. The parameters are examined over a transparent gateway-based TCP network after developing a mathematical model for the proposed retransmission-based mutant QoS-0. The probability model is then verified by an actual physical network where the repeated content delivery is explored at VM-based MQTT, local network-based broker and a remote server. The results show that the repeated transmission of contents from the sender improves the content delivery probability over the unreliable MQTT-based Internet of Things (IoT) for developing smart cities' applications.
Subject(s)
Internet of Things , Internet , Cities , Telemetry , Models, TheoreticalABSTRACT
Cooperative E-H (E = B, Si) bond activations employing κ2-N,S-chelated ruthenium borate species, [PPh3{κ2-N,S-(NS2C7H4)}Ru{κ3-H,S,S'-H2B(NC7H4S2)2}], (1) are established. Treatment of 1 with BH3·SMe2 yielded the six-membered ruthenaheterocycle [PPh3{κ2-S,H-(BH3NS2C7H4)}Ru{κ3-H,S,S'-H2B(C7H4NS2)2}] (2) formed by a hemilabile ring opening of a Ru-N bond and capturing of a BH3 unit coordinated in an "end-on" fashion. On the other hand, the bulky borane H2BMes shows different reactivity with 1 that led to the formation of the two dihydroborate complexes [{κ3-S,H,H-(NBH2Mes)(S2C7H4)}Ru{κ3-H,S,S'-H2B(C7H4NS2)2}] (3) and [PPh3{κ3-S,H,H-(NBH2Mes)(S2C7H4)}Ru(κ2-N,S-C7H4NS2)] (4), in which H2BMes has been inserted into the Ru-N bond of the initial κ2-N,S-chelated ligand. In an attempt to directly activate hydrosilanes by 1, reactions were carried out with H2SiPh2 that yielded two isomeric five-membered ruthenium silyl complexes, namely [PPh3{κ2-S,Si-(NSiPh2)(S2C7H4)}Ru{κ3-H,S,S'-H2B(C7H4NS2)2}] (5a,b), and the hydridotrisilyl complex [Ru(H){κ2-S,Si-(SiPh2NC7H4S2}3] (6). These complexes were generated by Si-H bond activation with the release of H2 and the formation of N-Si and Ru-Si bonds. When the reaction of 1 was carried out in the presence of PhSiH3, the reaction only produced the analogous complexes [PPh3{κ2-S,Si-(NSiPhH)(S2C7H4)}Ru{κ3-H,S,S'-H2B(C7H4NS2)2}] (5a',b'). Density functional theory (DFT) calculations have been used to probe the bonding modes of boranes/silane with the ruthenium center.
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PURPOSE: Diffuse mega-aorta is challenging. Prior studies have raised concerns regarding the safety of the open two-stage elephant trunk (ET) approach for extensive thoracic aortic aneurysm (TAA), specifically in regard to interstage mortality. This study evaluates the safety of the two-stage ET approach for management of extensive TAA. METHODS: Between 2003 and 2018, 152 patients underwent a Stage I ET procedure by a single surgeon (mean age 64.5 ± 14.8). Second stage ET procedure was planned in 60 patients (39.4%) and to-date has been performed in 54 patients (90%). (in the remaining patients, the ET was prophylactic for the long-term, with no plan for near-term utilization). RESULTS: In-hospital mortality after the Stage I procedure was 3.3% (5/152). In patients planned for Stage II, the median interstage interval was 5 weeks (range: 0-14). Of the remaining six patients with planned, but uncompleted Stage II procedures, five patients expired from various causes in the interval period (interstage mortality of 8.3%). There were no cases of aortic rupture in the interstage interval. Stage II was completed in 58 patients (including four unplanned) with a 30-day mortality of 10.3% (6/58). Seven patients developed strokes after Stage II (12%), and three patients (5.1%) developed paraplegia. CONCLUSIONS: The overall mortality, including Stage I, interstage interval, and Stage II was 18.6%. This substantial cumulative mortality for the open two-staged ET approach for the treatment of extensive TAA appears commensurate with the severity of the widespread aortic disease in this patient group. Fear of interstage rupture should not preclude the aggressive Two-Stage approach to the management of extensive TAA.
Subject(s)
Aortic Aneurysm, Thoracic , Aortic Rupture , Blood Vessel Prosthesis Implantation , Aged , Aorta, Thoracic/surgery , Aortic Aneurysm, Thoracic/surgery , Blood Vessel Prosthesis , Humans , Middle Aged , Treatment OutcomeABSTRACT
OBJECTIVE: The Kommerell diverticulum (KD) is an extremely rare developmental abnormality of the aorta related to an aberrant subclavian artery (ASCA). The objective of our study was to review the natural history of KD and ASCA using our single-center experience in diagnosing and managing KD and ASCA. METHODS: A retrospective review of the Yale radiological database from January 1999 to December 2016 was performed. Only patients with KD/ASCA and a computed tomography (CT) scan of the chest were selected for review. The primary goal was to examine the natural history of KD and ASCA and the secondary goals were to review the management and outcomes of those patients treated for KD and ASCA. RESULTS: There were 75 patients with KD/ASCA identified, with a mean age of 63 ± 19 years; 49 were female (65%). On CT scans, left- and right-sided aortas were present in 47 (63%) and 28 (37%) patients. A right ASCA or a left ASCA were present in 47 (63%) and 28 (37%) patients. Six patients were symptomatic on presentation. Symptoms included dysphagia, chest or back pain, and emboli to the fingers. The mean KD diameter was 21.8 ± 6.0 mm and the distance to the opposite aortic wall (DAW) was 48.3 ± 10.8 mm. Sixty-six patients were followed for a mean of 31.7 ± 32.5 months. One patient ruptured without repair. Nine patients underwent operative intervention, including eight open and one endovascular repair. Complications from operative intervention included ischemic stroke with hemorrhagic transformation, deep vein thrombosis and pneumonia. The mean growth rate for KD and DAW was 1.45 ± 0.39 mm/year and 2.29 ± 0.47 mm/year, respectively. On multivariable regression analysis, hypertension was a predictor of growth of DAW (P = .03). CONCLUSIONS: KD is uncommon and shows a female predominance. The diverticulum grows, albeit slowly (KD and DAW growth rates of 1.45 ± 0.39 mm/year and 2.29 ± 0.47 mm/year). Most patients are asymptomatic, but dysphagia, chest/back pain, and distal emboli may occur. Rupture is rare. Symptomatic patients should be operated. Asymptomatic patients can be followed with serial CT scans.
Subject(s)
Aorta/surgery , Cardiovascular Abnormalities/surgery , Diverticulum/surgery , Subclavian Artery/abnormalities , Vascular Malformations/surgery , Vascular Surgical Procedures , Adolescent , Adult , Aged , Aged, 80 and over , Aorta/abnormalities , Aorta/diagnostic imaging , Aortic Rupture/etiology , Aortography , Cardiovascular Abnormalities/complications , Cardiovascular Abnormalities/diagnostic imaging , Computed Tomography Angiography , Connecticut , Databases, Factual , Disease Progression , Diverticulum/congenital , Diverticulum/diagnostic imaging , Female , Humans , Male , Middle Aged , Postoperative Complications/etiology , Retrospective Studies , Risk Factors , Sex Factors , Subclavian Artery/diagnostic imaging , Subclavian Artery/surgery , Tertiary Care Centers , Treatment Outcome , Vascular Malformations/complications , Vascular Malformations/diagnostic imaging , Vascular Surgical Procedures/adverse effects , Young AdultABSTRACT
The outbreak of 2019 novel coronavirus disease (COVID-19) has become a major pandemic threat worldwide. Such a public health emergency can greatly impact various aspects of people's health and lives. This paper focuses on its potential risks for reproductive health, including the reproductive system and its functioning, as well as gamete and embryo development, which could be affected by the virus itself, drug treatments, chemical disinfectants and psychological effects related to panic during the COVID-19 outbreak.
Subject(s)
Coronavirus Infections/psychology , Pneumonia, Viral/psychology , Antiviral Agents/adverse effects , COVID-19 , Coronavirus Infections/drug therapy , Coronavirus Infections/epidemiology , Coronavirus Infections/physiopathology , Female , Humans , Infertility/virology , Male , Pandemics , Pneumonia, Viral/drug therapy , Pneumonia, Viral/epidemiology , Pneumonia, Viral/physiopathology , Pregnancy , Pregnancy Complications, Infectious/epidemiology , Pregnancy Complications, Infectious/therapy , Reproductive Health , Stress, PsychologicalABSTRACT
The reactions of dimetallaoctaboranes(12) [(Cp*M)2B6H10] [M = Co (1) or Rh (2); Cp* = η5-C5Me5] with different chalcogen sources, such as Li[BH2E3] and Li[BH3EPh] (E = S, Se, or Te), led to two unique reaction outcomes. For example, the formation of 10-vertex nido-[(Cp*M)2B6E2H6] (3, M = Co, E = S; 4, M = Co, E = Se; 5, M = Co, E = Te; 6, M = Rh, E = Se) from compounds 1 and 2 is a typical representation of a cluster growth reaction, while the formation of arachno-[(Cp*Co)2B6H9(EPh)] [E = S (9), Se (10), or Te (11)] is a rare method that yielded arachno clusters, keeping the core geometry identical. The formation of arachno-9-11 is a unique method that converts disobedient cluster 1 to obedient clusters 9-11. Further, the reactivity of nido-4 with various metal carbonyls presented sequential cluster growth reactions, which afforded 11-vertex nido-[(Cp*Co)2B6Se2H6{Fe(CO)3}] (7) and 13-vertex fused closo-[(Cp*Co)2B6Se2H6{Ru3(CO)8}] (8). The core geometry of nido-7 is uncommon and very similar to that of [C2B9H11]2- with a unique open pentahapto-coordinating five-membered face.
ABSTRACT
BACKGROUND: After aortic valve replacement (AVR), suspected prosthetic valve dysfunction (mechanical or biological) may arise based on echocardiographic transvalvular velocities and gradients, leading to reoperative surgical intervention being considered. Our experience has found that 4-dimensional (space and time) image reconstruction of ECG-gated computed tomography, termed cine-CT, may be helpful in such cases. We review and illustrate our experience. METHODS: Twenty-seven AVR patients operated previously by a single surgeon (who performs >100 AVRs/year) were referred for repeat evaluation of suspected aortic stenosis (AS) based on elevated transvalvular velocities and gradients. The patients were fully evaluated by cine-CT. RESULTS: In all but 2 cases, the cine-CT strikingly and visually confirmed normal leaflet function and excursion, with no valve thrombosis, restriction by pannus, or obstruction by clot. In only 2 cases did cine-CT reveal decreased mechanical valve leaflet excursion. Repeat surgery was required in only 1 case while all other patients continued clinically without cardiac events. CONCLUSIONS: Echocardiography is an extraordinarily useful tool for the evaluation of prosthetic valve function. Increased pressure recovery beyond the valve and other factors may occasionally lead to exaggerated gradients. Cine-CT is emerging as an extremely valuable tool for further evaluation of suspected prosthetic valve AS. Our experience has been extremely helpful, as is shown in the dramatically reassuring images.
Subject(s)
Aortic Valve Stenosis/diagnostic imaging , Aortic Valve/diagnostic imaging , Heart Valve Prosthesis/adverse effects , Tomography, X-Ray Computed/methods , Adult , Aged , Aortic Valve/surgery , Aortic Valve Stenosis/surgery , Echocardiography, Doppler , Female , Heart Valve Prosthesis Implantation , Humans , Imaging, Three-Dimensional , Male , Middle Aged , Reoperation , Sensitivity and Specificity , Young AdultABSTRACT
OBJECTIVE: The importance of triglycerides (TG) level as a risk factor for cardiovascular diseases (CVD) has been extensively investigated in the general population; however, their relationship in patients with type 2 diabetes mellitus (T2DM) is uncertain. We aimed to assess the association of TG with CVD in T2DM individuals. RESEARCH DESIGN AND METHODS: We searched bibliographic databases for studies published until June 2018, reporting on the relationship between TG and CVD in T2DM people. A random-effects model with inverse variance weighting was used to compute pooled estimates of the most fully adjusted risk ratios (RR) and corresponding 95% confidence intervals (CI) according to TG categories, unit TG, and logarithm (log) of TG for CVD. RESULTS: A total of 31 studies were included, involving 132,044 T2DM patients with 10,733 incident cardiovascular events. The pooled RR (95% CI) of CVD for an increase in baseline TG, log TG by 1-mmol/l and categorized in the highest vs. the lowest TG in T2DM were 1.06 (1.02, 1.09), 1.30 (1.18, 1.42) and 1.30 (1.16, 1.46), corresponding to a CVD risk increase of 6%, 30% and 30%, respectively. The pooled RR (95% CI) of CVD for per 1-mmol/L TG increment in eight studies and TG categories in three studies were 1.03 (0.98, 1.08) and 1.39 (0.92, 2.1) in T2DM patients adjusted for other lipids parameter, respectively. CONCLUSIONS: In T2DM patients, an elevated triglyceride level cannot serve as an independent marker for an increased risk of cardiovascular events, but still, the higher serum TG levels tend to be associated with increased risks of CVD.